This is like asking parents to choose their favorite child!
Choosing a platform to buy Jackbox Games on depends on a lot of things. Keep in mind that games are not transferable between platforms, so if you buy on one and decide you want it on another, you will need to make another purchase, so this is an important decision!
One popular use case is bringing a laptop with the games to a friends house. If that's the case, Steam is the way to go. Nintendo Switch and set-top boxes like Amazon Fire TV or Apple TV are also very portable.
Powerful platforms like Xbox One and PlayStation run the games really well, and the Xbox One X and PlayStation Pro render some of the games in 4k which is very pretty.
Ultimately, the decision is up to you!