We already know it's profitable so we also have that patience because it needs time to increase our investment, it's not an overnight success.
There is a qualifying statement about getting rich quickly when in terms of investing to online casinos that accept third party investors like us. We can get rich litteraly if we invest very big amount of money as a little house profit means a big gain for you when you invested big - but the risk is getting higher though.
You also risking your huge amount if you're investing a huge amount in any casino bankrolls because this is high risk and reward investment. Like how you can make profit similarly you may also lose very big amount if someone wins a big amount. If you're ready to take that risk then better diversify your funds instead of keeping all your funds in any single casino bankroll to reduce your losses.
It depends. If you invest in a large casino which has millions in its bankroll then its fairly safe, unless the site is somehow hacked or it leaks the provably seeds.
However if you invest in a newer site, then you are at risk because a large portion of your investemsnt will be used for each roll pretty much and with enough variance, some whale can completely clean out the site; like it happened in the past with many small sites.
Scamming scenario of those little site you've mention is the best basis for those people who keep looking to invest on certain sites around and they should research on the site where they want to go since scamming incidents can be avoidable but it need proper precaution. And the best thing really on this is to go on big sites so that we will not be worried for the result when days ends on our invested money there.