Applying egg wash with a spray bottle powered by compressed air, electricity, or elbow grease instead of a brush (the more typical and time-consuming method) has been common in European bakeries since the early 1960s. The spray technique makes a lot of sense. Not only is it faster, but it also produces a smooth, even application. Moreover, because you do not actually touch the product, you do not risk damaging the soft dough. The only disadvantage is that you will, of course, be applying egg wash to the sheet pan or baking paper around the items you are spraying, but this small amount of waste is offset by the advantages.
It is a good idea to designate an easy-to-clean area in the kitchen for spraying, or be sure to place a few sheets of baking paper around where you are working to aid in cleanup. For the best result, egg wash for use in a spray bottle should be prepared a day ahead to give the salt time to make the eggs less viscous.