You probably don't need these, unless your SUP doesn't already have bungee cord rigging, or some other method to hook your deck bag's snap hooks to, but instead uses "plugs". In that case, these can provide an easy way to attach the hooks of your deck bag to your paddle board's plugs. Just thread the loop through a plug, and then pass the loop through itself once, like a surfboard leash attaches to a surfboard. Now you can leave the loops permanently on your board, and you're good to go anytime!
An example of what are called "plugs", which look like this: