Putting huge amount, I think that is not common to gamblers, most gamblers are putting a small amount but want to have a big win, the reason why they lose most of the time due to the low chance of winning.
Actually there was a guy named TheFinalizer on stake who was betting like 5-10 bitcoins bet per roll and while these type of gamblers who roll high are rare but they do exist and that guy rained a lot in the chat so he must be winning too.
I think these people also aim to win, but they can easily let go of the loses since in the first place, their mentality was different to those who seek profit, for them, enjoy then win, and if they will not win, they would still enjoy.
Even I bet small and play for fun but when I loose there is actually not so much fun because if I am making a bet I have hopes on it and somewhere consciously I know that I would be winning so when it loses there is not so much fun.
I don't know how people hit such high amounts like winning £500,000 on a £0.30 bet is just crazy and I would die of heart attack if I hit something like that lmao.