I like this idea more as a GM than as a player, stange as that may be. If someone loves their character and spends a decent amount of FP, let them. Losing a character could break their participation and even with resurrection still gives fear of death. The diety's demand can help move the game along.
A creative Dungeon Master could add this to most settings except a real world one. A science explanation could be cloning.
As a player, I like grittier games, but I may get attached to a character one of these days.
Edited: iCon on 17th Jan, 2016 - 2:10pm
Having options can never be a bad thing so long as those options aren't as easy as pushing a button. Giving a role-player an option for resurrection or the end of his character cannot be a bad thing.
I like the idea. While I always have several potential backup characters planned out to level 30 in the d20 systems I play (Star Wars Saga, Pathfinder, FFd20, Dungeons & Dragons 3.5, etc.), I get really attached to my characters. Having that green toadstool to give me an extra chance on a flub is always nice Specifically early game before I have the chance to get my defenses properly set.
Perhaps the deity sees potential in the hero/adventurer or knows of a destiny the character do not, thus is willing to offer their life back in return for a favor or service? At least, I see such as a possible reason explaining why.
Just throwing out an idea but it might be a good option to have your familiar resurrected too with maybe not as harsh a penalty as if you are resurrecting self (Character).