Yep, Lisandro, the discussion about this is upcoming.
What is the lesser of two evils, to allow Bitcoin mining inside the browser for free webcontent or allowing ads.
Malicious mining or malicious ads are both a big no no and should be blocked and come alerted by avast's.
I expect Google is frowning upon Bitcoin mining as it is not part of their business scheme (yet).
For the moment I choose to block both ads and miners as I do not know their true nature as no-one could guarantee a 100%.
Damian