Because you also need game controllers etc. But that's where things suddenly get complex.

Sure, you are limited to only playing games in your Steam library.And just doing a quick test and it all seemed very slick and easy (it all runs through steams big picture mode). It then basically mirrors what is happening on Steam onto the TV (in 1080p for 2016 models and in 4k for 2017+ models). But then I discovered that, with Samsung smart TVs from 2016 onwards, you can download the Steam Link App for free onto your TV. But with the current price of consoles, it seems a bit of a luxury to have both. I've always been primarily a PC gamer, but I do enjoy sitting back with some mates and mashing buttons with some Tekken or similar running on the TV. Upside of Xbox One controller: most steam games use the xbox button layout/symbols. A good place to buy is Amazon US, where you can buy a controller plus wireless adapter for less than the price of a separate controller locally. A specific wireless dongle is needed and can be hard to find locally. Also make sure they are connected to your network with wires.

Tl:dr version: If you are thinking about doing this, make sure your PC and 2016+ Samsung Smart TV are close enough / same room (YMMV). Hopefully, this can help anyone else who might go down this route. Thought I should post my experiences here, as this was a bit of process and the info on the web can be slightly conflicting.

Steam link samsung smart tv