Wire: you need 3-conductor wire for the NEMA 14-50 versus 2-conductor wire for the wall connector, so the cost of wire is less.
The mobile connector charges at 32A on a 50A line, the wall connector charges at 40A on a 50A line and if you chose to run a 60A line it charges at 48A.
The mobile connector has a 20’ cable while the wall connector’s is 24’
The wall connector is updated via WiFi and at some point it will offer additional features. It also includes power sharing, which was an update delivered by WiFi.
And the cost
Mobile connector: outlet ($80), GFCI breaker ($150), mobile connector ($230), and some sort of cable management system for say $35 totals $495.
The wall connector is $425 + a $15 breaker, which totals $440, so it is cheaper as well.