Forget dice rolls, they've done something even worse:
Yobit actually has a coronocoin listed for trade:
https://yobit.net/en/trade/CORONA/DOGEWith every little piece of news I hear about them I always have the feeling they can't get much worse than that but it seems they can and they do...
As far as that investbox offer goes, I don't know what's going on in the minds of the anonymous folks who run Yobit. It could be a ploy to drive traffic to their site in the hopes that people will use their other services as well, but other than that I'd be hard-pressed to try to figure out what they're really doing here. I'm pretty sure it's not going to benefit their customers, though.
One of the usual requirement for the invest box is that you have to hold a number of yo tokens and have no sell orders for it since YO is created out of thin air this ensures the guys behind yobit a constant demand from newbies and a low sell pressure so they can dump themselves enough to make two or three times what they give the users in the investment box.
Once the math is showing that they lose money on one they change the requirements or drop it altogether and come with a new coin.
And yeah, the customer will always get screwed, but it seems the pond will never run out of fish.