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.