Is there any point to begin wearing a chinstrap 13 days post surgery?

I had a lower facelift and tightening of underlying fascia and muscle on April 15. My doctor removed a small amount of fat under my chin using scissors. The stitches were removed on April 28, at which time I was told to wear a chinstrap. My neck has minimal bruising and swelling. I don't understand what the point is to start wearing a chinstrap two weeks after surgery. Thank you for your opinions.