I refer to church as the body of people with whom you share the same or similar ideas. As they grow, they will invariably have a larger building to accommodate all Souls for worship. Some prefer smaller groups and some like the larger groups. In my place of worship, anything above 13 people, is known as a Centre, but yes, I meet those who prefer the smaller number of devotees as it's not so claustrophobic for them.
The real question is: How does the group or church help? I mean, you can pray at home, can't you? Lots say this. The trouble is that the group study together and can add inspiration, can encourage us when we are low and we will find that our prayers are more effective in the group.
I will stress that this can also happen on ones own, but one may lack the discipline of the group and soon backslide. It is good to move around in different groups as they all have different charismatic leaders and as such different or subtle differences in their approach.Hope this helps.