What do you get from upgrading the firmware? I have a 10 yo smart tv that I simply treated as a dumb tv. Works fine.
Mostly bug fixes relevant to higher end home theatre setups. Typically bleeding edge stuff where a TV is released before a new HDMI spec is fully baked or whatnot. One of my older OLED panels needed a number of updates to get proper Dolby Vision profile support a few years back.
Typically not all that relevant most of the time to the average consumer, but if you’re having a persistent annoyance it’s worth looking through release notes from time to time.
This ignores that the vast majority of consumers actually use the smart tv features like the Netflix app. Then updates start to become far more relevant and eventually mandatory.
I updated my LG C5 firmware via USB and my Nintendo Switch 2 now says “Switch 2” on the home page instead of “Unknown Device”. So that’s nice I guess. Also it seemed to fix something with the 120hz HDR 10:10:10 signal when connected to my PC if I recall correctly that before resulted in poor image quality.