Everybody can see that :
1/ The coin is old, older than most but was never traded in exchanges. Usually, exchanges make minimal research, before listing, and they didn't list XRB before. It seems the chain was broken at some points, as i noticed. By chance, was the code audited since ?
The dev probably laid low for a long time. Maybe solving catchpas and building his stash of his own coin. That's fine with me and a pretty smart move as well. This coin is 100% distributed from solving captchas so to get an interest in it, the dev needed time off from developing in order to build his interest in the accepted way.
I think it's great. Others will complain. But what else can he do? It is an open source project.
2/ Developments were rare, it seems. Dev, at one point, disappeared. The last developments are from the community. How reliable is the dev. now ? What was the explanation for quitting at some stage ?
How reliable is any dev? It is up to the coin and community. If the market cap falls flat, maybe he will disappear. If the coin gets listed at bigger exchanges and he can turn his interest into a salary, then the coin will do well.
Like everything in life from riding in a car to eating food to taking a bath, it involves risk. The question is how well can you read the dev?