All USB-to-Ethernet adapters are pretty evil in my experience. Always terrible performance, often slower than WiFi.
replies(6):
(A) replace your WiFi adapter - download drivers from internet
(B) configure a router or other equipment (hard to configure WiFi without WiFi).
(C) stand up your Linux install on your laptop (easiest way to futz around until you get WiFi adapter working - but check chipset on adapter is compatible which the cheapest usually are)
You don't usually care about the performance. Just keep a cheap one in your box of shit - I need mine often enough. If you need high performance, then buy a high performance adapter.
In my case A) and B) are irrelevant because I only really own or deal with laptops now days, and they invariably have built in WiFi, but usually not built-in Ethernet!
Case (A) is common for laptops. I've had plenty of WiFi modules (M.2?) go intermittent connection on friend's Windows laptops over time (maybe component drift?). For Linux on laptops I usually replace the manufacturers WiFi module so I get something better supported (high reliability - used to be Intel). Some people upgrade their module e.g. to get higher spec WiFi.
For (B), configuring WiFi routers is often easier with an Ethernet cable and sometimes necessary (depending on circumstances), and you need a cable to configure many other devices e.g. point-to-point links or whatever.
The fact you have a WiFi laptop is exactly why an adapter is really useful.
I don't disagree that the uses you describe make them helpful in those circumstances, but I can't recall ever needing to do any of that myself. I'm happy with the built-in Wifi adapter and its drivers, and all modern routers can be configured/set up over WiFi, can't they? They create a default network when first turned on, or if you factory-reset them using the physical reset button.