Some pilots fly hang gliders, others microlights, other Jumbo jets, other sophisticated fighter aircraft. They have one thing in common - they all fly & they are all pilots, regardless of the technicality of it! And each one of them handles his/her flying equipment to the best it can be handled & fly. So it is with arrangers in the lives of musicians too.
That's a nice and convenient analogy for an arranger player. Playing an upper class arranger, you feel like a Jumbo jet pilot who has trained thousands of hours unlike the pilot of a sailplane. I hope you are aware of the limits of your "analogy" (just one example: the Jumbo jet pilot has to know details about how a wing is constructed or the individual components of an engine, whereas the arranger player usually does not have an insight in the inner sound architecture of a voice, as the user interface, display and manual don't even explain this to the user).