This teaches you how to putt under pressure, because as you reach 45, 46, 47, 48 - you don't want to start at one again - so you must make a good stroke.
The secondary benefit of this practice method is to your subconscious. As you hole putt after putt at this distance, your confidence escalates and you have less and less fear of these putts.
If you don't have time to go to the course, remember - you can practice this at home on the carpet. This drill is a great way to work on your putting stroke.