I'm currently playing a Swashbuckler who identifies herself as a "Pirate" that worships Cayden Cailean and Besmara (thematically appropriate)-I feel that a world that has functioning magic should have nearly EVERYONE worship on a regular basis.
The character will NEVER be a Cleric (WIS 7) but does have a holy symbol, and follows many strictures/habits of the faith.
Once in a blue moon, as a GM I would reward this kind of RP dedication by having the god grant a minor boon (randomly heal in combat, vision during a dream etc).
It helps with immersion in the game I think. With my Swashbuckler, I'm having the character trying to convince the party that Cayden is just the neatest of the gods, and deserves to be worshiped.
If the GM told me I had 'fallen' I would probably slap him and walk out. Or tell him that my character found her own way to pray, and no one could say otherwise...
OP, your GM sounds like a bag of dicks.
If I had my way, Paladins, Clerics, and the like would not exist, and this style of divine intervention would be the norm. Divine "spellcasting" always seemed weird to me. Hey Bob, how about the take your gods divinely granted mojo and bottle it or make some wands with it?