With Outlook, the capacity of a room is not visible (except perhaps in the name of the room). A direct search and booking of a free room with a specific capacity at a specific time is not even possible.
With Outlook, you would have to manually book a room for the time a meeting is still being coordinated. Most of the time you miss to delete those bookings and - as everybody in your company does this - you experience overbooked rooms. Scedule automatically does this for you and also releases rooms when they are not needed.