Even if it is random cryptocurrencies, though, if they're smart, the amounts of each of said currencies should add up—at moment of sale, when converted to USD—to a constant amount. In that case, it'd be random ratios of each currency, to fill in a crypto "instrument." (Actually, I would expect this to be true if they have any business sense at all, since the only way to be able to do their books is if they can track their costs, which is only feasible if they have a fixed per-unit cost.)

Or, to put that another way, rather than a lottery per se, this might be more of a crypto-backed Collateralized Debt Obligation issuance where people don't get to know which tranch they're buying. (Which is legal, AFAIK; if it wasn't, the 2007 mortgage bubble couldn't have happened.)