I'd be okay with it if choosing to do this on your website wasn't going to obviously incentivize hackers to inject this software maliciously on unsuspecting websites to steal money from unsuspecting users.
The more legit websites do this, the more cryptojacking will wreak havoc on the web.
And for those who say they ask for consent so it's okay, why do the CoinHive people still pay out for versions of the software that don't ask for consent?