Comfort access allows you to lock/unlock doors and unlock trunk with the fob still in your pocket. You can always push the buttons on the fob in the conventional manner to do the same.
I've had this feature since my 2007 328i coupe and wouldn't go back to not having it. Very convenient feature to just walk up to the car and grab the handle.
Grab the handle to unlock the door, touch the "spot" on the handle to lock all doors. Similarly, walk up to the trunk and grab the handle to unlock the trunk.
The "lock" button inside the trunk lid will lock all doors upon trunk closure. Procedurally, drive home, get out of the car and open the trunk, remove bags, push lock button, close trunk, and walk away. The car will flash the lights when the truck closes to indicate that the car has been locked.