Physical buttons don't move around, their position can be remembered, they give affirmative response when operated and they don't require the driver take their eyes off the road to use. NONE of these things are true for touchscreens. Basically anything the driver can reasonably expect to need while driving should be a physical control - indicators, lights, wipers, wiper speeds, volume, temperature control & aircon, demisters & defrosters, horn, cruise control, gears, parking brake etc.
It is also why reviewers, owners and safety groups are become increasingly critical of vehicles like Tesla (and Rivian) that remove physical controls from their vehicles. It has nothing to do with aesthetics and everything to do with cheaping out manufacture at the inconvenience and safety of the driver & passengers. EuroNCAP will start penalising vehicles that do it in their safety ratings and it can't come soon enough. But really it should be a legal requirement for certain functions to be physical and the form they should take.