- set an empty looper to record "1 bar then overdub"
- arm that looper to record so the arm indication bar goes red
- press the main Play
- looper does not "record 1 bar then overdub", it just sits there looking all prepared but not doing anything
if a user has armed the looper and then pressed 'main play' they probably want a synchro start of the looper with the main play (in this case to record one bar and then overdub).
I can't think of a case where a user might arm the looper and then press main play and not want the looper to start.
pressing arm before 'main play' is associated with setting the master tempo, which is no longer an appropriate function once main play is pressed.