[realaravinth]

I am, but what I said was more of a hypothesis than a fact :)

From what I understand of reCAPTCHA, the model isn't static and is continuously learning from every interaction[0]:

> reCAPTCHA’s risk-based bot algorithms apply continuous machine learning that factors in every customer and bot interaction to overcome the binary heuristic logic of traditional challenge-based bot detection technologies.

I don't know the energy demands of such a system.

mCaptcha, under attack situations, will at most take 5s of CPU time on a busy (regular multitasking with multiple background process) smartphone.

[0]: https://www.google.com/recaptcha/about/