My dad, music reading mandolin player professionally taught, always called himself a "professional amateur"..he could play with anybody but rarely did for money in his day..I like that name..

As to arranger vs workstation, I think first of left hand usage to differentiate. Being an accordion player first, I use the limited left hand triggering functions an arranger has, not full piano style left hand (most) workstation users are. Then the OMB versus sideman utility. Styles vs no styles..Distinct differences designed toward different end users that keep the two separate and required alternate options. Can you imagine one model vehicle from each car company with same options for all?

Of course there is marketing and re-naming..today's SUV / yesterday's station wagon..