Sure. Computer-speaking it makes sense. The idea described in #648 is that human time is limited and spam is feeding on it as its prey. And when one is allowed to write here for free, that is an invitation.

Yes, paid spam will be possible anyway, but the spammers will never recollect those invested sats back simply because humans who would spend their time will also see through and not do any other actions (i.e. not vote for it with their sats).