I used to knit combination but have since switched to continental. I think there are patterns with twisted stitches that don't come out right if you knit combination.
I always wondered about those knitting directions that specified KBL when I always knitted through the back of the loop!
I didn't know that combination knitting was an actual "thing" and thought I was doing it wrong for the longest time. It wasn't until after I switched that I found out it was an acceptable way to knit.