There are not many high rollers that play like that. We've got a max win of 20 BTC per roll so they would have to go 1.2x with a 79.17% win chance. Need some balls to do that.
Do those HRs mainly Martingale? Palms be sweaty, knees weak, arms are heavy each time the bet is doubled.
Depends on his stack I think. You shouldnt stick to Martingale if your bankroll isnt huge or you may get wracked in no matter of time. Imagine he starts with 1 BTC and has a loss streak for eg 5 games. He would have lost 1 + 2 + 4 + 8 + 16 BTC at the blink of an eye.
You shouldn't stick to martingale unless your bankroll is infinite.
I repeat, INFINITE.
No matter what the amount is, 1 or 100 or even 1000+, sooner or later there will be a round where you'll have to go all in to save your initial bet which is probably a few thousand sats. If it is lower, it is even worse.