my 2c
* the way unicode input works in qmk is pretty janky imho. this is not something you can plug into any random computer and expect to always work perfectly without doing any configuring.
* you can accomplish the same thing if you have qmk (or similar) based keyboard by throwing the symbols on another layer or whatever you prefer. for $140 you can get a whole keyboard.
the keycaps are a nice touch though
QMK won't allow you to search for the symbols, which is a big limitation since there are hundreds of them