I use github and do a fair amount of Ruby, but I can't say I find Atom to provide enough benefit to move from a native option. I would have to see it used in more example cases to make that leap.
That code was only used past numerous safeguards that required multiple access codes/keys. The actual activation code was trivial compared to the layers of security necessary to use it.
Probably not ideal given it's financial situation, but the userbase may respond positively, and that could have a proportionate benefit that outweighs the negative.
The unexpected costs would be tied to game elements (like higher levels) that required IAP. If this wasn't made clear when the app was downloaded, it would be a deceptive means of marketing a paid app as free.