The LG built-in system is actually pretty nice (and the reason why I buy LG TVs). Netflix and Prime Video are a click away. If I have downloaded something, I just plug a USB stick or use the built-in software (SmartShare) to stream from my computer by WiFi. If I want to play some games in the Steam Deck, I plug it with an HDMI cable and it just works. If I want to show my kid a Youtube video, it's a little more inconvenient with the on-screen keyboard but not a big deal. By the way, I have a Sonos Amp connected through HDMI Arc, feeding two wired front speakers and two wireless back speakers, and it works with many versions of Dolby surround sound - I haven't bothered to check if this is easy on PC, but I suspect it might not.
Maybe it's just that I don't watch a lot of TV so I'm not fussy, but I haven't found any particular feature I would like to have that isn't reasonably easy with my smart TV, while I do find significant drawbacks in the PC setup (basically more stuff in the living room, why would I need a keyboard or mouse there?).
So yes. I'm a nerd, and I like my smart TV. Go figure.