You not going to lose your investment. If you lose money so does the website you investing is and why would they want to lose money ? Its actually one of the best investments you can make since losing hurts the house way more then you. Its in % so of u just lost 1% of 10btc the house just lost 1% of 10000btc make sense ? Put your money there andnforgrt about it. Everything has risks dont listen to these people that saynits a bad idea and you can lose everything because you won't and it is a good idea.
Stop posting BS. Of course he can lose. House has mathematical edge, but that doesn't prevent player(s) from being lucky and draining the bankroll. He could also lose to scammy operator who can disappear with funds (as we've seen in the past) or he could poorly choose kelly option etc.
Key factors to consider whether or not to invest in the site are: 1 - do I trust the site owner(s) enough, 2- what's the ratio of daily wagered and current bankroll (and what will be your % of bankroll).
Also, investing in house should always be considered a long term thing, if you don't have patience - don't bother.