I've made two thru-hiker quilts using the non-folded seam on the left. I can't say I've had enough experience in the field to know whether there is a risk of ravelling/blowout (hasn't yet).
We sewed some scrap together with a 1/2 inch allowance, untrimmed. No issues when we tugged and pulled. And honestly, this isn't a garment that gets a lot of wear and tear. We were more concerned about the stitch quality/tension. These are dissimilar materials.
It's obviously less work than folding, but if you don't mind a lot of ironing or careful handwork, it would help eliminate that nagging feeling you could've done more...
BTW, I used the edge of 1" blue masking tape to mark the baffle seam lines. It made it very easy to see the nanoseeum against the black liner. This was for a 12/5 karo step: