Excellent question @leprechaun
It's not a 0% house edge, that is just a marketing gimick. There is a house edge the way I see it, it's just that there are some cases when the edge is 0. There might also be like a commission system, like a fee charged when playing or something like that. But rest assured there is a revenue stream , which is paid out to EDG holders.
Amp is awesome, and very underrated project, I see an easy x10 price increase there. I already made there almost 400% profit, so I don't know why people are criticizing it? But much more profits are on the way in my view.
I don't like Gridcoin, it's one thing that there is a useful project and there is another thing that it doesnt generate revenue.
Same with Namecoin, very useful project, but I just don't see a profit there.
I like the idea of Namecoin, but I agree with you that there is no profit in it. Namecoin is missing something very important: Browser acceptance. There are no browsers that use Namecoin domains natively. That's why domains like xyz.com sell for hundreds of thousands of dollas whereas the xyz.bit isn't likely to fetch you fifty bucks. Lack of good governance.
There are servers you can set your browser to use when bit is used but that's a hack. I open any browser in the world and I can open steemfiles.com. steemfiles.bit? Why bother?
It will eventually come around in my opinion. But I would not invest in it yet. It's on my watchlist though.
Life is full of surprises