In the past when I was really into old bikes I rode countless hours on bikes with downtube or bar end friction shifters. These days my fleet is almost all modern, but I do still have one classic steel bike with a friction downtube shifter for the front mech.

Friction shifting performance (speed, smoothness) can be 10/10 perfect with good shifters, a modern chain, and a modern cassette with close ratios. But friction shifting always requires more rider input and forethought than indexing, usually requires taking a hand away from where it would otherwise be resting on the handlebar, and doesn't work as smoothly when jumps between gear ratios are larger.

So I have nothing against friction shifting, but at the same time, unless I'm deliberately building or restoring a classic bike there's no way I'm choosing friction shifters. I might make an exception for some Growtac Equal shifters if they were available to me, but I'd have to find the right project for them...