Regarding the original post.
@currier has done a fair bit of trial and error on site with spraying plaster. The material forms a skin and gradually causes blockages. This makes perfect sense as it does behave this way to your trowels. Unless BG have changed the formula then i would heed to what they state on their bags which is not suitable for spray application.
The spray suitable finishes don't do the same so there must be a difference.
My own opinion is its messy and pointless. The machine may apply a 100 m2 area in 20 minutes just as you would if 4-5 plasterers came helped you lay on. BUT... how can less people finish it ? The material is following a setting pattern and applying the plaster is only 1 process out of a minimum of 5.
BY Hand If 1 man puts 25 mts on the wall in a normal set it takes the best part of 3 hrs to finish it. If he puts 50 mts on he will be working very hard and that set will take much longer than a normal set to finish. No way can you maintain quality ,cleanliness and prepp for next set as you would in a normal set applied by hand.
People might tell you different but i speak from genuine hands on experience and nothing else.
My position is if they extend the setting times it could be useful, but the mess issue should be addressed (dust sheets wont last long dripping in wet skim everyday) 1 big spray first thing and then prepping trowelling and cleaning the rest of the day. There should be a clear advantage and labour/time as there is with using a machine to apply other products.