I recently decided to use the Ethernet port on my Roku Ultra, despite not thinking it was necessary.
I typically don't use my TV's Ethernet port, as my streaming experience is smooth and buffer-free. However, after reading some comments, I decided to give it a try.
I plugged an Ethernet cable into my Roku Ultra, which is located near my modem, making it easy to connect. I was able to hide the cable under rugs and along walls, avoiding any tripping hazards.
I didn't notice anything
The result was that I didn't notice any difference in my streaming experience. Author's summary: Roku Ultra's Ethernet port made no difference.