I can understand the intention but in the real world they have helped save time and efficiency of cleaning does have an aspect of time to it.
Glides save me time by not having to lug a fan or two into the home to get decent dry times.
Glides also save me time by allowing me to work throughout the day and not wear myself out so I can keep a good pace up all day long which enables me to produce more in one day.
Glides allow me to use higher flow which saves time by not having to do as many wet passes to properly rinse the fiber.
Glides may slow some down by having to vacuum but I believe that it should be done regardless of glides.
High flow actually allows for deeper and better rinsing and in effect uses less total water and I don't have to hunt for spigots as often which saves time! (only applicable for under 12 flow most likely)
Also glides save my customers time because they don't have to stay off the carpet as long as they would before! Due to faster dry times (this could also be related to the angled jets)
There are probably other reasons but those are the ones that come to mind for me!