Takes less time than if you were assembling on a ceiling you could reach without ladder, scaffold, lift...Thanks. This is contrary to what other here say...some say it takes less time.
on a 10 foot ceiling maybe not an extreme difference, you are still able to carry more items with you on a lift than on a ladder as a general rule and it can go faster than it does on a ladder because of it. If you are doing a simple task on low ceiling like just installing a trim, it could be possible that the ladder is faster, or if there is obstacles to have to maneuver the lift around that can slow it down.
If you have a situation with a boom type lift, you may be able to reach multiple luminaires without having to move the base of the lift, that can speed things up.
Lots of things to factor in and every install will have it's own set of those factors.