You can do all the work you want in making your own tracks or buy them. I edit pro made midi tracks and sing/play along on tunes you just can't do on an Arranger. People don't care or even know whats going on.
First time I saw such a thing it was a guy I knew to be a good guitar player and singer. Sitting behind what looked like a piano with a curtain on the front he sang all kinds of stuff. I went to say hello and behind the curtain he had three things on a table.
A drink, an ashtray, and a CD player !!!
A long time ago a good musician friend gave up his keyboard and went out as the "Singing DJ " Jerry Tolve, look him up on YouTube. Made his own tracks on a computer and he's a good singer. Still doing it to this day in upscale restaurants in North Jersey.
Sadly it really doesn't matter and comes down to what make you preform and feel better.
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Bill in SC --- Roland BK9 (2) Roland BK7M, Roland PK5 Pedals, Roland FP90, Roland CM30 (2), JBL Eon Ones (2) JBL 610 Monitor, Behringer Sub, EV mics, Apple iPad (2) Behringer DJ mixer