Many car infotainment/navigation systems suck. Android Auto and Apple Car play do not suck (as much), and the bigger car screen is great for maps.
Additionally, some cars will show the nav instructions on the dash, my car shows an arrow of the direction I need to go and the distance until then. Reduces the need to look at the map constantly wondering which turn to take.
For anyone who drives to different places regularly, doesn't want to buy a dedicated car gps, or pay to update in-car maps - a phone is the way to go.