I spent my entire career being involved in heavy equipment maintenance and have always done all my own vehicle and motorhome maintenance and repairs, and as a result, have a couple of comments about this lube-n-lock contraption.
Although it is a neat idea, and would work well, providing that all the grease zerks were easy to access and orientented in such a way that there was sufficient clearance to allow this straight, long greasing mechanism to attach to the zerks.
In reality, at least for my motor home and vehicles, I see this device as a gimmick, as the orientation of most all of the zerks on my vehicles and Motorhome do not have sufficient clearance to allow this long device to be able to be attached without using a 90 degree adapter. And if you have to fiddle around with the bulky lube-n-lock device, and manipulate the 90 degree adapter to reach the hard to access zerks, I feel this will be more difficult than just using a regular conventional grease gun fitting.
I use a rechargeable battery operated grease gun, with a 36" Aeroquip 'super gem' flexible hose equipped with a 90 degree end grease fitting, and I can grease all the zerks on my vehicles and motorhome in a very timely manner, with very little effort, and don't have any issues with the grease fitting dislodging from the grease zerks.
Just sharing my personal comments.