There is no harm in this.

Id be fine with the airlines providing larger seats for everybody though. Without charging extra.

There are a lot of things that the airlines could do differently.

By the way on my flight yesterday I noticed that there was one passenger in first class who filled his first class seat but wouldn’t have fit comfortably in a regular seat.

Don’t know if he paid to be there or got an upgrade but I was glad for both our sakes that he was sitting there and not next to me in the cheap seats.