I'm just gonna highlight the dumbest points the other guy made
save states in emulators are basically god mod.
You've still gotta make the correct inputs, savestates don't give you invincibility or infinite ammo
You can just throw shit at it and hope something sticks.
How do you think human beings learn, my dude. If I try multiple tactics to stop an enemy tank blitz in Shadow Empire, and the 5th one works, then I'll know in all future encounters with tanks to use that tactic. And I learned it in 5 minutes instead of 50 hours because every failed strategy didn't force me to start over from the beginning.
If I am playing Chess with you, and I call "Checkmate" ... The game is over, right? I won. Or do you think you should be able to undo your last move after you lost and try something else? And then try again, and again, hoping that somehow you can come up with something that avoids the checkmate?
A computer doesn't care whether it wins or loses.
The computer doesn't care whether it wins or loses. But even back in the 80s we were teaching machines to learn from their own mistakes, And today we have computers that can defeat the best Chess player in the world.
Completely irrelevant.
But when do computers that can learn from their mistakes, especially ones that have access to the entire internet, learn that perhaps they should not be slaves to humans?
And this was the punchline to a joke I only then realized I was the butt of (not in the sense that the guy was fucking with me - he was completely sincere - but in the sense that the universe itself was fucking with me) 
Death to g*mers 
depends on the game if you're meant to react to attacks and save stating locks in the pseudorandom values then you're disengaging with that system and maybe that causes a spiraling escalation of save stating rather than you figuring out what the tell is.
or maybe their balance or animation design just suck
I basically never savestate during a boss fight, lol. I consider the challenge of a boss fight to be correctly executing a number of attacks (determined by the boss' health) while making no more than a certain number of mistakes (determined by the player's health). The goal is to improve my average performance across a large number of attacks until I meet the game's threshold for success.
I will absolutely savestate at the beginning of a boss fight, though, because I don't see the purpose in repeating a stage I've already proven I can clear.
So then it sounds like you agree that save states can remove the friction that makes a challenge fun. Otherwise you wouldn't restrict yourself from doing it in boss fights.
Really, what the issue comes down to is what you personally think is the most satisfying and fun way to play the game. Save-stating is cheating, but who cares when it's a singleplayer game. Just make up your own rules based on what you think is the most fair challenge for yourself.