The same way one sets up any stupid network device that comes with a 192.1.1.1 default address: you stick a USB network adapter into the laptop, connect temporarily, while sitting next to it with a 1ft cable, connect to the web UI, set the value, and disconnect. Dough!
One can always invent silly conundrums that aren’t any.
Why? Added cost (a decent WiFi7 AP costs north of $100), added cables, added device that needs setup, firmware updates, power supply, power outlet, …and lots of other things that eat time and can break and complicate chasing down issues. Meanwhile the hardware available goes unused. Not my idea of efficiency nor my idea of a clean setup. It’s clutter and a hack.
Yeah, bloat 
the few bytes a WiFi driver requires, which gets loaded on demand anyway. Linux had WiFi drivers when main memory was measured in megabytes and single core CPUs were standard. Talking about bloat in the context of modern hardware is just ludicrous. Even a RasPi the size of a chewing gum stick runs the Linux WiFi stack with ease. 
Because an USB ethernet adapter I have around for traveling and device setup/debugging, not for permanent use. They are both dirt cheap, don’t require setup or drivers (beyond the USB class drivers), and they disappear in the travel kit right after the setup.
No, I don’t need to buy anything, I have that stuff already, and even if I had to buy it, it’s dirt cheap.
I don’t get why you go out of the way trying to tell me what I need or don’t need and what hacks I should use instead of a clean setup with Linux WiFi drivers. If you don’t need WiFi, don’t use it and/or don’t put your vote in, but there’s no need to try to sabotage others, just because YOU don’t want something. I’m not telling you how to use your system, either.