[PunchyHamster]

First one is problem because it brings no traffic back and occasionally DDoSes the site

Second one is problem because it DDoSes the site. "Just" queries for hundred thousand people (if you happened to be good source for that bit of knowledge) that don't bring actual people to your site is also a problem

[inigyou]

First one is not occasional, it is the anonymous global adversary probably ddosing your site right now. It never relents.