Yes, I understand the concept. But, your very example here illustrates why I have a problem with it. When you die, you die. There should be no get out of jail card here (or fate point) because that takes away from the challenge of the game. It coddles players. Epic classes tend to do this already with "When you go negative or die, you actually are often healed more than you were before you got hit". WTH???
I had the same thought when Action Points came out in 3.5 and were a D6 add to a D20 roll. In that case, it is a meta-game solution instead of an in character solution. It's an "after the result is found to be unsatisfactory, we will change the result". 4E's Action Points are much better. Although a player can use an Action Point after s/he finds out what happens with a Standard Action, it isn't a direct modification of the result. It's an additional chance, but not the same action and it's totally in character, it's not a "opps, let's back that up".
Fate points are modifying what has already happened or already failed in the game. They are a "Wait, back up, let's just change that because I don't like it as a player, ok?" system.
I have a bit of an issue with Immediate Interrupts for this very reason as well. They change the result based on the fact that the player doesn't like the result. They are very player entitlement oriented and I prefer a game of "what happens, happens". Sure, bad die rolls are going to come up. That's why all PCs should have some rare "go to the well" abilities that they can unlease when it happens (in earlier versions, low number of charges items such as a few more powerful than normal potions could be used to go to the well). But, those abilities shouldn't be "Waaahhh!!!! I don't like what happened to my PC. I want to change it.".
Limiting fate points to specific aspects of the game system doesn't change the fact that they go back in time and change what actually happened in the game. It's like saving a computer game, doing the next challenge, and then when you find out how to beat it, you go back to your saved game and do it all over again, using the least amount of resources and gaining all of the benefits for you character.
Why is there such a drive in our gaming community to make D&D like computer games? I'm sitting with a group of people roleplaying because I do not want to be playing a computer game.