I recommend it if you are
top-stitching around the top edge of a bag. It helps the fabric to feed more evenly through the machine and gives you a better result overall.
Binding clips are another quilting supply that carries well over to bag making. When you are sewing bags, you often work with multiple layers of fabric.
It is essential when you are constructing bags to reduce the bulk in the seam allowances. If you have a lot of bulk in your seam allowances, you will not get a smooth finish outside your bag.
I always cut my corners at a 45-degree angle to the corner. I then use a 2 point turner, Hera tool or other “pointy” object to push the corner out to be friendly and crisp.