It’s great for Tesla, for one reason - modularity.
Not really as far as the touch controls on the steering wheel goes. The icons are static and can’t be changed, so their functionality is kind of tied to the icon.
As for configuring additional controls for them, it’s exactly the same as if they were physical buttons, it’s all a wiring harness going to the computer either way, what that computer does with the input signal is not any less configurable for a physical button. The limiting factor is the static icon, not whether it’s touch/tactile.
In regards to selling incomplete products, this is unfortunately not even limited to Tesla. All car manufacturers release several updates and bugfixes for new cars, they just can’t send them OTA, they need to get them in the shop. My colleague’s VW ID4 has been in the shop for no less than 3 SW updates to fix various bugs and add basic features such as battery preheating for DC charging, it fucking shipped without that!
The menu controls on the screen are snappy and load as quickly as you’d expect from a regular phone/tablet. Miles ahead of all other manufacturer’s which indeed always seems to be slow as hell.
Web browser and Netflix/Disney+ are still fucking ridiculously slow on the “older” though. It’s been significantly improved with the new hardware in the model s/x and 3 highland refresh, but still not good enough IMO.