As far as I can tell, their ReLinker solution is only a workaround to the installation problem.
Actually, now that I think of it, I can see a business requiring employee devices to be flashed with a set of apps but not wanting to put the effort to actually check that it'll work. In that case the developer should determine if the user is an individual or a company and in the later case sell them a contract for support.
Hmm, I always shared apk files with friends when they simply were too big, kinda easy to do with ES File Explorer or other root-using file managers. Lucky for us, our CPU archs never proved to be a problem though.
But I can very well imagine this being a problem for warez, or people in countries not served by Google Play (or who simply have no easy access to payment, e.g. because they don't have a CC), or people with devices not sold with Google Play (cheap ass chinese phones).
I guess it should be pretty simple to add a "wrong version for your device" killscreen to an app, once you realize it's a problem.