Most of those websites that are technically "wasteful" in some ways, are way more "wasteful" when you realize what we use them for. Mostly it's for pure entertainment.
So either entertainment is wasteful, or if it's not, spending more compute to make the entertainment better is OK.
I would say most websites are wasteful wrt the customer, which is usually advertisers. There are websites where the user is the customer, but they’re rare these days.
So either entertainment is wasteful, or if it's not, spending more compute to make the entertainment better is OK.