Well scopes started out with external adjustments. They dont have them anymore because they were not as good or reliable unless you used them only in certain climates and a clean enough environment.
If you have external adjustments then they are exposed to the weather and particles. Imagine having that thing in an environment that has fine particles of sand and or dirt. I would imagine it would become useless after a day once the fine sand and dirt worked into the mechanism and wore it down so it was no longer usable or just locked it up. I have had it happen with adjustable gadgets that had the adjustments exposed to the elements. Also think about freezing climates. Where I live if I went out hunting with something like that and it was anytime between September and July theres a good chance it would get frozen up and not be able to be adjusted.
Theres a reason why scopes moved to internal adjustment. In order to keep the precise movements needed to accurately adjust optics the mechanical parts need to be protected. If this actually has fully protected and sealed parts then disregard these statements but the photos looked like it probably isnt sealed up tight enough to keep fine dirt, sand or water out of it.
If you plan on using it in controled environments where dirt,sand and freezing water wont be present then maybe it will function correctly for you.
I dont see scope manufacturers dumping the precise protected turrets good scopes have these days to go backwards in technology. If you buy a quality scope you dont have issues with turrets failing, Think about the snipers and target shooters who take shots out to 1 mile and farther when you start talking about scopes needing to be optically zeroed and the turrets not being able to hold adjustments consistently. Those shooters are using 20 - 40 moa bases and maxing out their elevation knobs and still holding over because they have run out of adjustments. Those scopes are not anywhere near optical zero and they are making good hits using the scopes that way.
I have 3 vortex pst viper scopes with all of them setup with a zero stop and a 100 yd zero for them all. I can grab any of the 3 rifles they are on and crank the elevation and horizontal turrets to max and dial them back down the spot they are set for my 100 yd zeros and take them to the range or hunting and take a shot with no worries of the zero being off. Before you ask if I have done it yes I have. One of my buddies will walk by and grab the turret and start twisting it just to be funny if I have it setting on the bench at work. No problem I just dial it back down to the zero stop and its back on the 100 yd zero. I have used leupold, bushnell tactical and night force scopes and they all can be dialed up and down and they still work as intended and hold their zeros.
This device seems to be an answer looking for a problem that doesnt exist. A member posted about being handicapped and not being able to use the turrets on a scope to adjust it and this device would help him. If a device is needed to use a piece of gear due to a handicap then yes it has value and a use for that person if the device will hold up to the elements and maintain its accuracy. For people without a handicap I see it as a step backwards from a good quality scope at least this particular device in its current design.