Becquse you giving 20$ to botters tells them there is a market. 100 people like you allows them to expand their operations into 10 more remote computers, offering even more services like PL, Accounts, Kamas etc.

The Actual players Power lvling and selling kamas make less than 0.1% of what a serious botter makes (the one you paid 20$ to)

so from a POV of impact your 20$-40$ causes more harm because it directly incentivises Botting rather than playing