What exactly is boosting?

I agree. I see a lot of posts where people think they can solve the PvP gearing problem but it might sound good on paper but never the same in practice. Which is why each expansion I look forward to the PvP changes and just hope it is something that benefits me. As much as everyone hated Ashran I actually enjoyed it a lot and was in there most expansion. Got all the achievements from it and glad I did. I also enjoyed Wintergrasp and Told Barad too even if there were fundamental problems with them.

Yes but the point is they are effectively cheating to earn places in grps they are not qualified to be in

Paying gold is not cheating tho. It is an exchange of services.

No different than buying flasks from an alchemist because you did not bother to level one up.