OP, DH and I use that loop to put the seatbelt through all the time. It helps to secure you. I am 5'6", DH is 6'0", and we both weigh under 160 lbs. When DH sits in the seats, his head comes up higher than the arrow indicated in the picture, but mine doesn't. I must be REALLY short waisted or something. Anyway, we both use the loop to put the seatbelt through- for us, it doesn't feel very secure if we don't. You are sort of 'tipped back', so sitting up in the seat probably won't be too much of a problem, but like other posters have said, there is no side support.