In my time with the R09-class, and possible uses as a standalone.... I've used it in the sample here, and, had a need for it another time.
That other time,.. *[rolls eyes, smacks forehead, feels sick smilies here]
I was at an organ recital. I was rushed, and needed a battery for my mma6k. I bought a new one at a convenience store en route. New battery dies before end of first set.
I could just use the internal mics, right? You'd think...
Nope, I totally forgot about them, and folded up shop. *[apply same smilie set here]
Let me tell you about the time that I used the DR70D internals,... without knowing it. I'd somehow gotten confused in the manual, and turned the internals on, and then dropped the deck into my recording bag, and recorded those two channels from inside my bag, thinking that I was on external mics. This one sucked. But it did explain the weird reaction to attempted level changes for those two channels.