In my opinion, there is not much creative about jotting down some chords in BIAB (or similar), selecting a style, and hitting PLAY. i'm sure THAT could be done by a well trained chimp (well actually he wouldn't have to be that well trained). Seriously, what Diki said above could certainly be applied if that's your approach to starting a project. In fact, I myself use pre-recorded drum tracks or drum tracks I constructed using drum machine software and I always do this FIRST as I play along in my head. So I guess, in a way, I'm doing the same thing, just to a lesser degree. Where available, I ALWAYS prefer a live drummer, but only if he's good (with time and taste).
Another problem with non-realtime programs like BIAB is the difficulty in using them (or their creations) on a gig. Ignore this if you aren't gigging. What do you do with a request that's not in your song file? Hum it? or maybe call a break and start furiously typing in chords? or just be honest and tell the requester that your computer doesn't know that.....yet. At least with an arranger, if you know it or can quickly bring it up from your digitized fake book, AND can play, you can probably hack it and get that $2.00 tip (that's where those years of music lessons come in)
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The point is, no one that can play even a little bit, is ever going to trade in their arranger KB for BIAB. They may buy/use it IN ADDITION TO their keyboard, especially in a way as described in Diki's post. But let's face it; that old adage is still true; 'you get what you pay for'. Your old, outdated laptop, your questionable taste and talent, and a $99+ program is not going to be a viable substitute for a Genos or PA5x.
PLUS, doesn't the primary joy in this business come from PLAYING? JMO.
chas