Good stuff! Every time one of these companies starts it makes me feel bullish about the future of BTC. I think a brokerage is a good idea because dumb people are going to be intimidated by the process of buying BTC on their own, some people are far more likely to invest if a trustworthy company can do it for them. These finance industry people aren't going to open BTC companies if they even have the tiniest idea that BTC will fail. It doesn't mean much but it gives me confidence that the price will explode within a number of years. Fingers crossed that mainstream adoption isn't too far away.
Well, of course it is also a gamble they are willing to take. But again ,we know nothing what these companies do with the bitcoin. If they are earning commission off the trades, they could be just selling at the market price on spot and have all the math done accordingly.