I'd claim services being ad-funded is not dissimilar from being funded by a JS crypto miner - which is to say while it does move money to that service, it's on net a waste of resources and average affordability would be better without it.

For instead of your ISP spending 20% of their resources advertising (because otherwise they'd lose market share to ISPs that are advertising), they could likely offer email hosting and basic web hosting without you paying any more than you do currently. Competition between companies should be directed towards productive ends (improving their product) else it just becomes a giant zero-sum game of resource wastage.