[brudgers]

As described, it appears growth will depend on social network effects. The current standard strategic advice would be to build something a few people love. Out of that falls the tactical advice to make something that can be put in front of a very few potential users right now, collect feedback, and quickly iterate.

In the US, and possibly other markets, there are potential legal impediments due to gambling laws. Worldwide, there may be acceptance issues among payment networks.

In broad strokes, I wonder how an app is better than exchanging cash in terms of "the important thing isn't that I won, it's that you lost" in the social context.