I don't think there is any argument that physical buttons are easier to use without having to look once you build up a muscle memory (which is why touch screen TV remotes are rubbish). But the advantages of having the buttons virtual rather than physical is something Tesla believes in.Yesterday, after considerable searching I found out how I raise or lower the heater temperature. Trying to do that whilst dribing (IMO) is dangerous (at least as dangerous as answering a cell phone (which is illegal).
If you cannot operate the temp control safely when driving then you need to either to wait until you are stationary or try the voice control.
PS it is only illegal to directly answer a cell phone call if the phone isn't in a fixed holder. Given that the Tesla screen is fixed and doesn't need to be held still, the law doesn't agree with you that it is just as dangerous.