It is cool and possibly quite useful. Definitely a good engineering challenge/project. Others have already pointed out some safety issues and a few others have

It is cool and possibly quite useful. Definitely a good engineering challenge/project. Others have already pointed out some safety issues and a few others have then questioned likely are those scenarios. For me though one of the big downsides would be while traveling. This thing would never be allowed through airport security as a carry-on. It looks like mini knife like objects encased in a soft rubber casing. Yes, one can always take it off and store it in a checked-in bag. But if you forget then you will be forced to choose between dumping it or not boarding the flight. Not to mention the extra cavity search one might get as a bonus.