Giants can be a challenge for low level Melee characters. It's much easier for Archers and Mages, since they deal damage from distance and cannot be hit by a Giant. Fighting Giants can be good way of practicing your combat skills, especially Block and Armor skills.
Giant Toes have unique Fortify Health effect and is a very useful and valuable ingredients for Alchemists.
I don't understand why anyone would want to "fix" this "bug". It's so funny and awesome.
Skyrim is about immersion and RP, most long term players aren't in it for the combat gameplay. So, when bugs like this persist in the game, it kinda detracts a little from the atmosphere, thus sabotaging the main thing keeping most players afloat.
Don't get me wrong, it was amusing the first few times, but jokes are less funny each time they are told. It's not that big a deal, but I'd rather it was done away with.
In response to the rest of what you put there, I honestly never considered fighting giants that much. I should try it out, it could help me level a good bit.