Surely there is something interesting that can be done with something that has such unusual properties, even if it's a corner case. It's basically a single-use "transistor" or "valve" for mechanical force.
Does the glass explode with enough force to be used as the primary detonator for a high explosive? I'm no explosives engineer, but seems like having an all-mechanical (no chemicals, no electricity) primary detonator could be useful in some situations where the system should be very stable for decades, like car airbags.
What about emergency release valves? Plug the release channel with the tough end of the drop. Use a simple mechanical system to break the weak end if the emergency conditions are met. e.g. a lever attached to a float that snaps the weak end if the fluid level is too high. That should work safely even in an environment full of flammable material.
Getting into more fanciful territory, could a professional assassin create one that was large enough to work as a hand grenade? Or encase the weak end in a jacket and then use it as a bullet with the tough end being seated in the case?[1] Seems like it could almost be a real-world version of the mythical "ice bullet", where after use there wouldn't be enough left for forensic analysis.
[1] Here's a video of someone shooting them from a shotgun, but there's no jacket or spin-stabilization to keep the weak end pointed at the target: https://www.youtube.com/watch?v=lc9pPOrZ_0Q
It's only useless if you consider all art, games, and educational tools to be useless. Which is a very sad outlook.
Art: they look beautiful and can be displayed.
Game: breaking it, or watching it being broken, is a lot of fun.
Education: I would say that a huge number of people have been inspired to take up glassblowing after seeing one of these. But not only that, they also serve as a great tool to demonstrate that an object's physical properties are often unexpected based on appearance. I would say a decent amount of people have been inspired to study physics because of this too.
