Key difference
This is the same abduction movement with a dumbbell instead of a cable. Gravity pulls straight down, so resistance is near zero with the arm at the side and highest at shoulder height, whereas the cable loads the start of the raise. With range of motion matched, the two produced similar lateral deltoid hypertrophy in trained lifters [1].
When to choose it
Choose this as the default replacement when no cable is available or for home training. Both arms can be trained at once to save time. Dumbbell increments are large relative to the loads used, so adding repetitions before adding weight is the usual way to progress.