Idols in the Hindu temples are not toys or statues. They are physical bodies which have been energized to vibrate in a certain way such that they impact everything around them.
The entire concept and the science behind the idols and their handling are given under Agama Shastra, a tantric scientific methodology that has been perfected over many millennia.
The idol as indeed the entire temple becomes a vibrating body that can impact any person that is in the vicinity of the temple. This practice of energizing idols was traditionally known as “Prana Prathishta“, literally meaning Establishment of the Life force in the idol. In English, although not completely consistent, we could use the word consecration for it.
Researchers say that this was initiated for the increasing concentration during prayers. According to psychiatrists, a man will shape his thoughts as per what he sees.
So when we worship the idol, we can gain spiritual energy and meditate without mental diversion.