Assuming that 1% is even true (I'd say that's an overestimate), the other 99% of the time, ads are distracting, misleading, and manipulative, all in ways that are bad for your mental health because they make you feel like you're not safe enough, your life isn't interesting enough, you don't have enough, etc. Even if, like me, you're fastidious about unsubscribing from ads and blocking ads, advertisers are adept at shoving their shite in front of you in violation of your consent.

Cryptocurrencies are pretty bad, but at least if you ignore them, they don't find you and directly harm you.