Well, it doesn’t look bad for what it is. But I can’t see how this beats the ortlieb, other than cost and availability. They can really be put on and off in a single motion and still be secure. There is no need for a permanently attached mount on the bike. How would I even get my hand in between the bag and the wheel to tighten that grip? Without getting dirty?. The mount appear to have sharp metal edges exposed when the bag is not attached. Will the lid be tight from water coming underneath? When biking it’s not just rain from above.

Ortlieb has other variants of the bag that are easier to open without loose straps. If you are happy with requiring a special mount only for your own bike there is the 3.1 series with even more snug fit and less protruding hooks on the bag.

Best option with ortliebs is to add a second hook which stops any chance of the hook jumping out over rough terrain