I have often thought of using a flat rope nylon webbing rode, for space and weight saving. The cost is significantly more than the nylon double braid I use now with a fortress anchor for my 20ft 3,500lb boat on the mud and sand bottom of the Delaware and Chesapeake.
I have never had a dragging problem and rarely anchor in more than 20 ft depth in the Delaware River and Bay with its large tidal current range.
Unless you cover the webbing, from your hawse hole to the connection to the anchor, you can expect very short service life and significant loss of strength due to the long term UV exposure.
When using nylon 'rope', either 3-strand or double braid, the very same section will be noted have quite severe UV (burn) degradation ... but only on the external diameter.
Polyester probably should be the choice because it withstands UV exposure and with less degradation, much better than Nylon(6
); polyester tubular webbing is very 'rare'.
The same UV effect is easily noted in jacklines (used with teathers) when long term / long distance sailing when left on deck for a couple of months exposure.