As far as I know the "other times this has been tried" all have had individual displays (and controllers) in each key. The difference being that here there is just one panel under the whole board with most of the parts above the display being transparent. This approach should be far less complicated to build, more robust and cheaper.
Honestly, I don't think I need an LCD in my keyboard but I'd quite like to have a go on some mAgLeV hall effect switches! On that note, if you like magnets and/or keebs you might be interested in Void switches[0] -- 3D printable hall effect switches
Honestly, I don't think I need an LCD in my keyboard but I'd quite like to have a go on some mAgLeV hall effect switches! On that note, if you like magnets and/or keebs you might be interested in Void switches[0] -- 3D printable hall effect switches
[0] https://github.com/riskable/void_switch