It's a difference if you make a 30 min walk, pass by a bakery in the morning and the supermarket or a restaurant in the evening. You can't have that in the car, or train.
I have a 40 minute work to work that passes by a bakery. Sometimes I take the bus which passes right by that same bakery. Sometimes I drive which passes by the same bakery. I have stopped in that bakery while driving, and while walking, it make no difference. In fact the car is more flexible because a 5 minute detour lets me stop by a supermarket that is an extra 15 minutes while walking. (the bus only comes every 30 minutes so stopping in the middle to run errands isn't practical even though it detours to that supermarket)
You pass by the bakery. You're not hungry… but it does look delicious. You go back, look through the windows again -- and decide you are hungry!
If you're in a car, you don't stroll around. You drive where you want to drive. Even discovering new things is hard since the people behind demand you don't slow down.
(this is loaded with personal experience and preference, I can perfectly understand this doesn't match yours.)
As a passenger, suddenly you become aware of all these objects and sights that you simply couldn't spare the time or attention to look at when busy in the driver's seat.
Fun recent anecdote, a coworker passed me in his car while I was walking to work, because of the time for him to park, we arrived at the coffee machine at the same time.