TPMS is part of a package, right? Pretty sure I don't have it. Mine is a stripper except bluetooth and mats.
It's required by law. As stated in the writeup, in the US,
a functional TPMS warning light is required in the US under Federal requirement FMVSS 138.......As of this writing, it's legal on a federal level to have a system that doesn't detect tire pressure due to dead batteries or bad sensors but the TPMS warning light or federally mandated TPMS system must not be disabled. A bad sensor, missing sensor, or worn TPMS battery will still be in compliance because the TPMS warning light will be on and the system is still working as intended.
Above that, the manufacturer warranty covers it so while the car is under warranty, you should have a working system. You must always have a working light.
Speaking of TPMS, is there any way to monitor pressure values or are they just hi-lo pressure switches?
In the rented GM cars I've driven, you can see tire pressure in the computer and (since I'm lazy) not having to bend over and check tire pressure every so often would be nice.
You can only see it through VCDS. Here's a screenshot. For the 2011 and newer cars they change to the ABS sensor based system which has no additional sensors. If one wheel's rotating diameter gets smaller than the others, the car assumes that it's low.