I'd probably attempt to monetize it, but it looks like he might be generating more buzz by not doing so, which is an interesting strategy.
He's going to be competing with clones that will flood the app stores either way, and users aren't going to necessarily know which one is the original (a past drama about 2048 comes to mind), so it's going to be down to whoever does the most marketing and manages to get featured in the app store, which is a lot of work and stress, and may not be worth it in the end.
I guess he decided that the risk/reward is not worth it.
He's going to be competing with clones that will flood the app stores either way, and users aren't going to necessarily know which one is the original (a past drama about 2048 comes to mind), so it's going to be down to whoever does the most marketing and manages to get featured in the app store, which is a lot of work and stress, and may not be worth it in the end.
I guess he decided that the risk/reward is not worth it.