I think arrangers are pretty special.
It's great to be able to "arrange" (or "re-arrange") tunes using different styles and instruments...the ability to edit styles is what makes them so special today...earlier arrangers only gave you a finite number of preset styles.
Also, the arranger is only limited by the imagination and skill of the player...yes, some people look down on them, but it's usually those who can't seem to (or don't want to) explore them fully and get the most out of them.
I like playing with other musicians, but I like using the arranger just as much.
The biggest benefit for me is the immediacy of doing arrangements, and, of course, the ability to do solo performances with the added edge of having the accompaniment.
Can't imagine life without them now, although I still love playing the piano and jamming with my buds on the B-3.
Ian
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Yamaha Tyros4, Yamaha MS-60S Powered Monitors(2), Yamaha CS-01, Yamaha TQ-5, Yamaha PSR-S775.