Is the knot on the bag strap decorative?

Looking across several of MARGESHERWOOD's GRANDMA USED bags, the same knot appears repeatedly. However, what that knot does differs slightly by product.

On the GRANDMA USED BAG LARGE, pulling both knots adjusts both the length of the belt strap and the shape of the bag together ^[1]. The GRANDMA USED BAG is a horizontally long tote bag, with knots placed on top of its belt strap ^[2]. On the GRANDMA USED SLING BAG, you can pull the belt strap to carry it like a tote ^[3].

Generally, methods that adjust length using cords or knots have no preset stages like holes or markings, allowing intermediate lengths to be used freely, but visual estimation is required to align both sides to the same length. hmmm, for those hesitating between buying the large or the small, this knot also means you can test out two different shapes interchangeably within a single bag.