The belief itself does nothing, rather it’s the knowledge that they can’t turn to their God for help, but have to take whatever they want from life with their own two hands. Most Cimmerians are not Conan though, and it’s not Conan’s non-worship of Crom that makes him the larger-than-life superhuman he is.
It’s certainly contrary to convention, which veers towards “everything must be balanced, and actions cannot have consequences because players are absolute morons that cannot be trusted to read and understand a single line of text”.
But why is that a problem? You’re right that the crux of the argument for the way it currently is, is that it’s entirely in keeping with the source material. Now I need an argument for why they should discard established canon? I applaud Funcom for sticking to their guns on this in the face of the “idiotic mantra”* from players such as you who can’t accept that there’s a choice in the game which is mechanically sub-optimal (you have to hunt down one more trainer to get the full benefit if you pick Crom, boo-hoo).
*your words, not mine
Sure, if all you contribute is “the others are idiots” you will get an unsatisfactory conversation.
Or call it respect for the source material. Something often lacking these days.
Conan himself takes the help of whatever God or spirit will give it, such as Mitra’s in The Phoenix on the Sword, even as he steadfastly refuses to worship them. Conan is “god-fearing” in the sense that sorcery and the mystical arts creeps him out (he’s still a savage at his core), but being Conan he’ll proceed to rip the head off anything that scares him rather than cower in fear.
If anything, picking Crom is the “right choice” for a character seeing the religion mechanics in a strictly utilitarian way (RP wise). And if it’s all about the gameplay benefits, just ignore the Crom option and pick something else. If I remember correctly the option even spells out that there’s no gameplay advantage to picking Crom? Or do pick it and spend the time finding the other trainers, it’s not like you’re locked into the choice.