if you feel that you want a capsule, then get one, if you dont think of it as "needed" then dont worry about it.
all kids are difrent, ive always used the reversible car seats, birth up, sometimes we could move them out of the car and they would stay asleep or stirr and be settled again, othertimes they would wake and be up. even now they are the same at 5, 3 & 1, sometimes they will stay asleep when taken out the car, sometimes they wont.

always go with what works for you, and what you are comfortable with. not everything works for everyone, babies and kids are no exception either!