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.
I mean all-in vs splitting it up does matter a little bit. If ypu are unlucky the very first roll, hand, spin, etc then you go bankrupt right off the bat. Splitting it up gives you a shot to come back from a couple early loses. Also i gamble for entertainment, nothing entertaining about going all in and losing right away. That seems more like a waste of money than anything.