I used the line in the op's pic to tie down my winter covers one year.... it is horrible! The cover is the most suceptible to abrasion I have ever in 50 years used. It stiffened so much after a couple months it wouldn't hold a knot. (I should have known when I uncoiled it when new and it wouldn't shake out the kinks) The "core" is simply untwisted/unbraided strands of poly. When the cover wears or loosens, the core strands pop out and part quickly.
For very little more money you can go to HD, Lowes, or Ace hardware and buy Derby line. Bright color choices and available in a couple different diameters. It floats, stays soft for years, holds knots well (doesn't splice), and suffers from minimal abrasion problems when used as a dinghy painter or dinghy dock line. Sold by the foot so you can buy only what you need. After 14 summers, I replaced mine for good measure but I am still using the original for misc. purposes around the boat.