There is at least one mechanical perk for not joining a faith.
There is a character class that can not join a religion.
People wanting to join religions has never really been the problem.
Priests who are active enough (and willing enough) to take on a high follower role are, in relation to the total number of religions the realms has been.
Trosis' idea of a symbol as a permanent fixture in a temple is interesting.
Perhaps in absence of a high priest, there'd be a specific temple for each faith to go and pray and get the temporary affects of their religion prayer.
I don't as much like the use of loyalty points for investment unless it is pretty steep and there is no active high follower.
With prays being logged, staff will always be alerted now to seekers and get it taken care of quickly as they are able; there is good RP potential there, and with other members of the church that could be happening.
Perhaps spending tokens for investment is something that can only be spendable after a 2 week period from character creation. You can literally be offering your loyalty