Although the existence of an infallible imam entails many benefits, but an imam in occultation also has its own numerous benefits which can be summed up in the following:
1- Being the mediator between us and Allah's (swt) divine grace
2- The people making use of his existence
3- Aid and inspiration in scientific and spiritual matters
4- Being the "proof" of Allah (swt) who rises with clear proof and signs
It is because of these and other benefits that hadiths say: "The world will never be without Allah's (swt) "proof" [the infallibles]."
The existence of the infallibles brings many benefits; some of them belonging to normal conditions when they are available. Yet, one mustn’t perceive that if an imam goes into occultation, his existence will be no longer of any benefit to the people. With help from hadiths and the sayings of great scholars on this issue, we will list some of the major benefits of an imam in occultation:
1- The upholding of clear signs and proof
No matter in occultation or amongst the people, the imams are the "proof" [hujjah] of Allah (swt) in this world [meaning that Allah (swt) has sent them to be followed, leaving no excuses for those who don’t], rising sincerely for Him with clear proof and signs.
Imam Ali (as) says: "O Kumayl! This earth will never be without the hujjahs [proofs] who will prove the universality of truth as disclosed by Allah, they may be well-known persons , openly and fearlessly declaring the things revealed to them or they may, under fear of harm, injury or deaths hide themselves from the public gaze and may carry on their mission privately so that the reasons proving the reality of truth as preached by religion and as demonstrated by His Prophet may not totally disappear ." Other hadiths with the same theme can also be found that confirm the fact that the world never lacks Allah's (swt) "proof" [meaning the imam].
2- Channels and mediators between us and Allah's (swt) grace and mercy:
Imam Sajjad (as) says: "We (the imams) are the means of the safekeeping of this world, we are the reason for the skies not collapsing onto the earth, the reasons why the clouds rain and the blessings of the ground emerge. If it wasn’t for us, the earth would swallow its inhabitants…The world has never been free of a "divine proof", the only thing is that sometimes he is present, while at other times, he is "absent" [which in reality means that he is unseen, not that he isn’t present at all]."
In the famous and great ziyarah of Jame'ah Kabirah, some of these benefits and blessing have been pointed to:
"It is because of you [the imams] that Allah (swt) sends down the rain, it is because of you that the skies don’t collapse unto the earth, and it is because of you that sorrows and harms are relieved of and adverted."
It is because of the imams that Allah (swt) showers His general and special blessings upon the people and the Shiites.
3- Making use of Imam Mahdi’s existence (aj) by the people:
Imam Sajjad was asked about how the people make use of an "absent" imam; the imam answered: "The same way people benefit from the sun when it is behind the clouds."
The same way the sun gives off light and radiation behind the clouds, the imam in occultation is a source of guidance to the people (whether they know it or not).
Muhaqqiq Tusi, one of the Shia’s greatest scholars says: “The existence of the imam is a divine grace, and the changes and things he does are another. The reason why he is “absent” [not seen by us] is because of our own actions [and has nothing to do with him].” What Muhaqqiq Tusi is trying to say is that him just being there and all the benefits that follow this presence of his are a great divine grace, although if he were to be seen by us as well, it would have also been another grace and other benefits would also follow.
Add to all of the above the fact that knowing the imam is present and aware of all that we do can factor greatly into many people moving towards virtuousness and righteousness [out of love and respect to the imam and because they know he is watching].
4- His aid and inspiration regarding scientific and spiritual matters which only belongs to the believers:
His Excellency pays great attention to the believers and Shia and prevents many calamities and disasters from taking place for them. He also helps those who have the capacity to reach higher levels of spirituality [sometimes with them knowing it, and sometimes not]. Imam Mahdi (aj) says: “We never forget you and it is because of us that Allah (swt) averts dangers [that threaten you].”
For further information, see:
1- The reason for Imam Mahdi’s (aj) prolonged life, Question 209-1405.
2- Logical arguments for Imam Mahdi’s (aj) being alive, Question 534-582.
 Nahjul-Balaghah, Saying 147; Al-Kafi, vol. 1, pg. 179.
 Mojtaba Tune’i, Farhange Alefbayiye Mo’udnameh, pg. 529; Biharul-Anwar, vol. 52 pg. 92.
 Mafatihul-Jinan, Ziyarah Jami’ah Kabirah.
 For further information, see: The Philosophical Basis of Mahdiism, Question 221.
 Farhange Mo'udnameh, pg. 529.
 Intizar Magazine, issue 5, pg. 130, article of Ali Rabbani Golpaygani.
 انحصار اللطف فیه معلوم للعقلاء و وجوده لطف و تصرفه آخر و عدمه منا Kashful-Morad, pg. 363. For further information, see: The Theological Basis of Mahdiism, Question 220.
 Mikyalul-Makarem, vol.1, pg. 271, quoted by Farhange Mo'udnameh, pg. 593.
 Jum'eye Entezar, issue 5, pp. 135-142.