It is almost a good idea. Once you get on the lanes with the bowling ball in you hands to take a full approach, or even a one step drill compared to this device things will change dramatically.
During the shut down we see all of the pros posting on social media different videos every day working on stuff from home. It can help some with staying in a bit of bowling shape especially with your legs, but it is no where close to how you throw the ball on the actual lanes.
When the pros are able to get back on the lanes and practice that is what separates them from the rest. As far as this thing goes, I'd save your $300 dollars and apply it to a lesson and actual practice.