Forward Roll Demonstration. Keeping good balance, traveling in a straight line, and coming up in a fighting stance. The 2nd part shows doing four in a row transitioning from roll to roll but finishing the last in a fighting stance. When done properly, one should be able to repeat the roll again and again while having a discussion. With training, rolls can be done on a hard surface without pain or injury.
Lots of great uses for a forward roll. Here is a brown belt level technique: dive over object, pick up weapon, pop up ready to use that weapon.