Open and focus file browsing dialog from command line
I have some Karabiner-EventViewer experience and found out that your "currentApplication()" is not Terminal, as one would think, but actually osascript.

Therefore …

osascript -l JavaScript -e "var app = Application(\"Terminal\");
    app.includeStandardAdditions = true;
    app.chooseFile().toString();"


… will at least give you keyboard control.