Not very (stupid) if you consider how easy it is to change between cars in the Lobby compared to the Arcade mode. In the Lobby to change between tracks and cars require a lot less steps than in Practice mode (in GT Life) and in Arcade mode. The downside is that unless you've organised a race or a track day (and if no else joined your room while you're in it), it's just you and the track. Of course being to see the sunset on both the Nurburgring and La Sarthe makes up for a lot of things.
(Also in for the online mode, tire model is in full swing meaning tire temperature and the degradation is ON as well as fuel consumption- you'll feel a distinct difference in how the car feel than the Arcade mode for example).