Recording without MIDI SYNC

I use Acid 4 when recording my beats I made on the MP
and I don't MIDI sync to record

what's the advantage of using midi sync?

Syncing the mpc to your multi-track software makes it easier to record individual tracks in time with one another. Let's say you want to record 8 seperate drum tracks but dont have the 8 out expansion, by syncing the mpc you can record one track at a time and all your tracks will be perfectly in sync with one another. If you were to do this without syncing your gear you would have to adjust all your tracks to line up in time with each other manually which isn't hard to do but can be time consuming.