The chances of influencing our thought process in a holy place are much better than in our own homes. Thirdly, rituals provide a frame work or an infrastructure to practice religion. It is no different than why we go to schools and colleges to acquire the knowledge rather than by studying at home. Rituals could serve as a source of inspiration and strength. Jain history is replete with stories where some souls made enormous spiritual progress while going through some kind of a ritual.
Rituals also add a variety.
If we do meditation alone, it could be tiring for many of us -laymen, after a while. Very few of us can meditate for an extended length of time. But if we do pooja, samayik, pratikraman etc. , our body and mind-both get involved in many different ways, making religious practices more interesting. And there is a social dimension to the rituals too. Social interaction, group encouragement are other benefits that naturally flow by participating in ritual events.