+1 for not using it with small spools.
I have several filament dry boxes, and I'll sometimes use it when feeding from those, but they sit above the printer so that tube is maintained mostly vertical.
When feeding from a smaller spool, next to, or in the printer, I do not recall the last time I used the extra tube. It seems more like a failsafe for using exactly sized flux spools from inside the top of the printer, but with anything else it isn't really necessary as long as your filament is clean and dry.
Any feed issues caused by filament quality problems are going to be discovered at the bowden extruder anyway, and you're definitely familiar with that.
In fact, the only reason I sometimes use it from the overhead dry boxes is that as spools get past the midpoint of winding, the 'curl' in the filament seems a bit tighter so having it run through the tube just helps to straigten it out before it hits the feeder.