If this game only attracts people interested in their ROI, you are most likely correct. However, I do not think that is a forgone conclusion. In fact, I don't think the devs are trying to attract that demographic at all. They are trying to attract gamers, not investors.

Investors only care about one thing: handing over their money in exchange for a future payout. Gamers are not thinking that way at all. They hand over their money in exchange for both immediate and future entertainment. If this game attracts people who are willing to spend some money in exchange for fun, then it will succeed. The fact that those players get a little bit of steem back will be a huge bonus. It will not be the main motivation. If the game is fun enough, I bet those people will either say "Cool I played a fun game and I got back a little coffee money" or they will just exchange it for something in the game that leads to them having more fun.

Attracting new players (and I mean players... not investors) from outside of steem's current user base is the only way this will succeed. A big part of that is the devs making an incredibly fun game that could become addictive like so many mobile games. However, another piece is the behavior of the early access players. Whether motivated by ROI or fun, those early player should only behave in a way that will make it more likely that new people will join and actually play the game. If we behave in a way that creates a miserable experience for a new player and they immediately leave, we will be shooting ourselves in the foot... and we need to save those bullets to protect our HQ.