"What deity does your PC worship?"
"They're a fighter, not a Cleric"
"Okay, so what deity does your *fighter* worship?"
— made up strawman argument in my head as a premise for this blog post
This is it, this is the crux. The hill that I die on. Your non-divine PCs should worship gods all the same. I'm going to be the GM that preaches their own party and I'm not going to be ashamed; My Rogue worships a custom pantheon of Desna, Calistria, and Pharasma. My fighter's been blessed by Ragathiel. My Wizard is known to Nethys, and the Cleric worships gods that don't even grant him any powers. They don't benefit most of the time, they don't earn the favor of their gods most of the time. They put in the effort to still worship, and the roleplay of such endeavors is extremely enjoyable for everyone involved.
Gods matter in Pathfinder setting. They exist, we've seen them, and the seeds of gods-to-be exist among us in the form of mortal souls. Mechanically, Pathfinder gives us a few solid benefits to worship — the classes Druid, Champion, Cleric, and Witch to name a few — but no such merit expressly exists for character classes that aren't powered by deities themselves.
If you take anything away from this post, it's that I want to see your players to be class-agnostic in how they worship the gods. We must accept that the blessed among Golarians are a strict subset of those who worship individual divine beings, and therefore our players should exist in this world by paying tribute to the powers that shape it one way or another.
We should be concerned with checking boxes "outside the character sheet" for our character. It's from my experience that this is how worldbuilding and roleplaying come together for the players. Seldom do I feel immersed in a game by simply knowing it's history, and it is imperative that we connect the wires of the story to the inputs of the player. Here's two lore blurbs to consider:
"The Goblinblood Wars lasted four years. The ruined encampments from the conflict can be found all throughout Isger, often derelict or occupied by bandits. In the waning months of the conflict, so much of Isger's natural resources were depleted to feed and house soldiers and to build fortresses and outposts throughout Goblin territory." Now this:
"[Our Monk] grew up in the worst crop shortage in Isger's recent history. The fruits grown on the mountain were made into rations for the soldiers, her family rarely had food when they needed it and sometimes no more than ale for dinner. Young still by the end of the conflict, she didn't understand that the end of the Goblinblood Wars is what brought back the berries and fruits — and to this day would credit her prayers to Jaidi for saying the family farm. Those prayers still come do this day, whether Jaidi hears them or not."
I'm not making a fair case here in comparing the two, since I obviously put a lot more effort into the second deliverable. However I want to make the case that you're not going to deliver a story through worldbuilding alone — you need to connect the big picture to the people in the world. Ask your party about their gods, their beliefs, the color of the saddle on their horse's back, and I think you'll be surprised at how real it all might start to feel.