To me the ease of having the library be installable with the "canonical" package manager of my platform is too convenient; just "feels" more natural and simpler. I actually thought about writing a node.js ngrok client but then gave up on the idea since localtunnel was working well enough and I personally didn't need the other features from ngrok which I didn't have in localtunnel.
I wouldn't worry about the whole rewrite in c thing. If your server protocol is simple enough, writing clients in the native languages will be better than writing bindings. Installing bindings trips up a lot of users that are not used to compiled software.