It is true. Partner sites make revenue for the partner through revshare and partners attempt to create fake clicks and even conversions to inflate their revenue. Cobra effect in play.

This risk is zero (except for things like ad neuseam) on first party / owned and operated placements like search/ig/fb.

As with anything you should verify your roi through third party measurement providers, just like you would do for others.

Disclaimer: current fb ads engineer, former google ads engineer.

Can you please elaborate? Your source is just an appeal to authority, but I would really appreciate more evidence to help explain your position.

By that logic any lottery winner could argue that lotteries are a great pension plan.

If they consistently win lotteries year after year with a good ROI, sure. Not sure how that comparison works.

Ever heard of survivor bias? Let me make an example: I choose 2048 random addresses. I choose I random company on the stock market. Half of the addresses I send a email stating the stock will rise in the next month, the other half the stock will fall. After a month I check the stock and disgard the addresses where my prediction was wrong. Than I repeat the previuos steps until only one address is left. Now ask him about my expertise on the stock market.