Looks like chipmlxer.com (SCAM!) just got a nice idea from you 

However, this is the most advanced scam, even maintaining session expiration time and renew/restore.

I think the new API is really nice but it is a matter of time until scam sites will use it:
Checking and redeeming sessions and vouchers entered or even providing fully functional scam sites, scamming only higher amounts to gain trust.
For sure, the latter can be done with own infrastructure, but with much more effort.

All scam sites lack captcha, just as observation.
Captcha is to protect from DoS, I think. That is also a problem for API, isnt it?
I think API is (or will get) a nightmare.

Anyone has a clue about how many these sites are making? I would start monitoring on my own otherwise.