Sry but I wouldn't recommend to use this plugin. Here are my reasons:
1. I don't see the case that user's really accept this. If you create a great game you will be forced to publish it on ios/android/steam. Conversion rates will be higher using payment methods of these stores.
2. Even if there is a case where early games are requesting donations per paypal you can just simply link out to your paypal merchant account. Everything is stored by paypal and it would feel better for the user. Imagine there is an API error happening that takes out money from the user but show wrong messages and users get confused.
3. The plugin is stated "early development" which is not good for anything that has to do with sensitive user data especially payment data.
4. I don't know if there is the possibility of double-checking the code by other users or if it is on github but sure this has the possibility for tricks like sending users money to a different paypal account.
5. The profile and website imho doesn't look very professional but at the end I would at least expect details about a registered company with address, phone and legal number so I have someone I can blame and sue if there is any kind of fraud happening.
Don't take it wrong. I am sure "h1k32" has no bad intention and I am thankful for every developer that is working on bringing more value to c2. But regarding serious topics like payment everybody should carefully check on if it is trustful. This is not like a twitter-share or google-leaderboard plugin were you just mess up some tweets or ranks.
So if someone really sees value in not using store payments or outgoing paypal links wait until it is software status is "stable", "validated" that there is no fraud code and "h1k32" showing valid comapny information.
Sure you can buy this to support development but don't use it on final published products (yet).