I often use YouTube as a tool, for instance for quickly learning how to do something by watching, and ad-free makes this a significantly better experience.
Also YouTube music comes with it, and I find it better than Spotify, so it replaced that account completely.
Ad revenue is always taking a slice out of somebody else's profit, and at the end of the day the profit is always taking the slice out some consumers wallet.
But if inflation is high, and consumer debt is rising (which it is), then eventually the consumers wallet is going to get much tighter, which will shrink those companies making things profit margins, which in turn has to hit ad revenue.
And yet every companies solution right now seems to be "we'll increase the advertising!" As if ad revenue was manna from heaven.