A friend lost a chunk of his crypto investments to a scammer that claimed his game was provably fair. The owner of the website waited till the website was popular, to accrue more victims. Then he simply closed the website and vanished with thousands of dollars belong to people.
The site you have mentioned on one of your replies here doesn't seem to be popular, at least on my own view.
First of all, why your friend test waters on the site that doesn't even have a quite good feedbacks and reviews available on any source. We are already risking our money doing gambling so why increase the risk more playing on a not famous site. Bonus? Promos? Perks?
Anyways, the damage has been done. The site is currently offline. No way to recover the funds. But that doesn't stop their shitty service. Surely one of these days, they will comeback branded in a new name. Hope next time, people will only stick to those reputable gambling sites that already established a good name in crypto gambling world.