The maul can be a fast method of retaining the ball.
It commits more defenders. It can continue to gain ground.
The dangers are when forwards and backs are separated in practice and the back-line players do not understand their role at the maul, or even back away from the contest.
With the maul, the gain line is fluid and the defence can be forced onto the back foot
With the ruck, the gain line is static and the defence are often set and on the front foot
Clearing the tackle area with pace relies on committed support. Clearance rucking is a dynamic method of restarting the attack if the defence has managed to create a breakdown.
The spinning or rolling maul is an effective weapon when executed at speed. Notice what happens to the pace of the attack when the ball goes to floor with a breakdown
Staying strong and maintaining a leg-drive when in contact can help to gain territory, give teammates more time to support, and sometimes, counteract the tackle entirely.
In this clip, Eastbourne College score a try against Eton as a result of powerful running and leg-drive.