You can sell accounts with high karma, but your hourly takehome would be much less than minimum wage. Then again, I can't argue about Kubernetes at Burger King, so working for HN has its perks too
If they want to downvote I think you need a certain karma level.
Do that with enough accounts and you can control the narrative on certain subjects such as downvoting/hiding all the Twitter news that is negative, or the latest FAANG layoffs?
Unlikely though. Perhaps to positively promote your new startup? But then you don't need karma for that, so I have no idea.
I guess on Reddit it might be considered a way of boosting the account's authority or whatever, but is there any impact to having high karma on HN?