The Delcro is one-size-fits-all, while the Elastic Loop is a fixed size with no adjustability. This means that the Delcro will likely fit your wrist better.
The material of the Delcro is softer to the touch than the Elastic Loop, and at the same time the Delcro feels more sturdy / has more structure than the Elastic Loop.
The Delcro is less elastic / stretchy than the Elastic Loop, but it's also less "scary" to put the Delcro on, because you don't have to stretch the strap like a rubber band to fit it over your wrist (which you have to for the Elastic Loop).
In short, in many ways the Delcro is superior to the Elastic Loop, but if you want a truly lightweight combo, the Elastic Loop is still king. You'll have to try them both out to decide!