It does depend on the implementation and interface and driver aids. As cars get more intelligent with lane keeping, speed management , obstacle and danger awareness then some driver load is removed. If effective voice recognition and read back is implemented, then there is no reason why access to some Internet functions should be any more distracting than drivers messing about with hunting up radio station or music sources.
At one time some 25+yrs ago I messed about in my old 200sx and installed all sorts of nonsense ambient lights and a full entertainment system that included digital and terrestrial TV, DVD etc. Whilst I admit to having had TV shows running while driving, I didn't look at the 4.5in screen – just used it to listen to the audio. It was handy during a 1-hour accident queue, though.
These days, I rarely have even a radio on when driving, which may be more distracting if one starts to think about 'stuff'
As for large car screens – the benefit is obvious with rear and side camera displays and less beneficial with unnecessary menus for car functions that used to be on ergonomically easy buttons
pgk