I believe that if we're playing a game with a house edge, where winning depends purely on luck, then bankroll management doesn’t really matter.
What you deposit is already intended for gambling, so whether you go all-in or divide it into smaller bets, the reality is that bankroll management won’t change the odds. It just adds an extra layer of stress in making decisions that, in the end, won’t really affect the outcome of a luck-based game.
You don't just get the purpose of a bankroll, do you? It's not mainly purposed to change the odds of the game's outcome but to rather create the layer of enjoyment in time as you gamble bit by bit rather than you going all-in-one. Like how do you get to enjoy the game by going in all-in one at once.
In my opinion it's even an act of irresponsible gambling behaviour that I should go all in with what's in my account when I could gradually make the most part with each session.Exactly, that's the point. It's very unsafe to do so because if you go all in once with your deposit, you could lose everything at once and wouldn't have any balance left to continue gambling and by so doing, you wouldn't enjoy the game you even staked on. Like you said, bankroll will not increase odds of winning but can make the player to play for a long time while their luck is being tasted.