For most deities, seizing faith is more convenient than developing it.
The reason is simple.
It's not easy to make a mortal worship you; even if you display great powers that could alter heaven and earth before them, they might only think you are "impressive," hardly enough to spark true adoration.
That's because there isn't just one deity in the world. Countless bards make their living by boasting about the greatness of deities, and even the weakest deity has had inspiring poems written about them.
A deity that can lift a mountain is indeed great, but as recorded in poems, some mages can do that too.
So is this deity really impressive or not?
Most mortals have no way of knowing and can only speculate.
This makes the spread of worship for deities challenging: you need to spend time making them understand your greatness, then accepting your doctrines, and recognizing the benefits of worship and the consequences of disbelief.
