Faith is one of the great aspects, which enables all the peoples in this world to attain god. To fulfill all their needs, the Perumal is giving his seva in the form of Idols) Vigrahams) in the temples.
Because of various aspects, some people might not be going to the temples to worship the perumal but at the same thing, they might be thinking of him always. Even to them and for their bhakti, the perumal himself is taken out for Veedhi purappadu (utsavar is taken out from the temple) and to give his dharshan to all the bhaktas.
Deity (Idol) worship and Purappadu:
Peoples are living by god's grace and the god giving his seva in the temples as Deities (Idol). An ordinary man cannot see the god so that he resembles like this. God will he seen only by great Gnanis and bhaktiman's. They differentiated his different types of roopams. Some of them know about god's mentality and they are explained about him well. These are the main evidence that we are worshiping the god's Idols in the temples. These Idols are very powerful to bhaktas. By spending our time with god's Idols in temples we are getting a mental satisfaction.
Some peoples may not be able to go to the temples and worship the Perumal. To satisfy them, the Perumal himself is going to their place to offer his Dharshan to them.
If we pray the Perumal with full faith, he will really rectify all our sorrow and sins. In this modern world, even the Perumal comes near us, we are least bothered to worship him. But, our Aacharyas, great Rishis have performed lots of Tapas to see him and to attain his Divine feet. So, it is advisable to visit the nearest temple to your place or atleast, worship him when he is taken out for Purapppadu.