Comment by II2II

I have a 2.5 GB/s USB to ethernet adapter. While I cannot say whether the performance matches that of built-in ethernet, transfer rates are fairly close to 2.5 GB/s. That is certainly faster than WiFi.

Oddly enough, point (A) is likely more relevant in the current world of laptops. At least if you use Windows. Plugging in a supported network adapter, may that be WiFi or Ethernet, may be the only way to get through the installation process, without jumping through hurdles, then install drivers for the built-in WiFi adapter, without jumping through another set of hurdles. (I own such a laptop, though I use Linux on said laptop so the WiFi just works.)