>>meisel+ta
Monero's proof of work (RandomX) is very asic-resistant and although it generates a very small amount of earnings, if you exploit a vulnerability like this with thousands or tens of thousands of nodes, it can add up (8 modern cores 24/7 on Monero would be in the 10-20c/day per node range). OPs Vps probably generated about $1 for those script kiddies.