A tailor's awl has many uses including:
- Help feed thick or heavy fabric through the presser foot. Expecially when sewing bags.
- Gives you a lot more control while you sew straps, binding and anything too fiddly to pin.
- Use it for poking holes in pattern pieces
- Use it for rotatin pattern pieces when patterndrafting (ie moving darts)
Check out this free tutorial by You Sew Girl which describes the use of a Tailor's Awl when seing up a purse strap.