what do you need midi sync on your recorder for? what would it be synchronizing inside the recorder?

i need this because most of the time i record in sync with other machines. for example sp-303+roland d2 or sp-505+yamaha qy70 etcetc. it's very precise and you can add other midi-rythm machines after recording. very practic and metronomically right.

Been pretty happy with my Micro BR. Kinda wish I got the BR 600, but the Micro has helped me in numerous applications. Instead of a drum machine it has preset beats, which are cool to jam over (Like with a Microkorg), then I sample my jams into the SP & have original riffs~

any opinions on the Pocket Studio 5 ?
They are pretty cheap and use batteries.