Latency. WiFi latency can spike which ruins video calls. Simple speed (given lots of time) on the other hand is rarely a problem.

There’s also the problem of sometimes, video calls just stutter and seize up and it’s the internet’s fault, not the local network. But with a wired connection, I am immediately confident the problem is not in my network. With WiFi, who knows, maybe it’s my fault. I used to continuously ping the router so I could verify this, and indeed ping spikes would happen. Now with a wired connection I don’t worry about this.

But yeah if you run no latency-sensitive applications, WiFi might be fine.

WiFi is convenient and (usually) cheaper (esp if it's a retrofit), but not deterministic. And less 'cluttered' I guess, if that's your pet peeve. All sorts of things can muck around with Wifi speed, reliability and latency and most people have little or no ability to troubleshoot it effectively.

I retrofit wired my house[1] about 20 years ago; I only have had a small handful of issues with it in that time (all basically mechanical fatigue of jacks). If I have speed, latency or connectivity issues, I can be reasonably sure the last thing I have to debug is the physical network.

[1] Copper, not fiber, but no runs are over 50m. Works to 10G so far. I used a Leviton residential structured wiring system (network, coax and phone at the time; the last 2 long since obsoleted). I did a lot myself since I'd done enough quality time in datacenters to be adequately proficient with low voltage Cat5. Not cheap but not extravagant.

It's potentially a problem in a typical brick house in Europe.

I'm sure it's less of a problem in houses with other materials.

The answer is brick and concrete. You’d be amazed how well a load bearing wall in a high rise will block a signal.

For me it's the metal studs in my walls. WiFi reception is truly awful. Fortunately it was prewired with Cat5e. But that will need to be replaced some day.