For most users/use cases, there isn't a need for for so many dedicated keys - if they are prepared to learn layouts with multiple layers. There are several notable advantages: cost, portability, reduced footprint (keeping hands closer together when using mouse and keyboard), and reduced finger travel/stretch. These last two are good preventative measures for carpal tunnel.
I chose a 40% ortholinear keyboard specifically because I make heavy use of the numpad in my work. I keep the numpad on one of four layers and I find using it to be quicker and more seamless to transition to than when using a full sized keyboard. I only wish that more manufacturers made ortholinear layouts....
I'd suggest looking at hollow wall anchors (also called umbrellas fixings) which are similar in design to the ones you're describing but heavier duty (steel) and designed to hold the weight of a radiator, though they can be difficult to use if you're just using a screwdriver (in my limited experience.) Also a new product called Gripit which I have no experience with but apparently are designed for this sort of thing. Seems quite a bit easier to use.