Kleopatra in the past used polling to get status information from the Gpg-Agent about Smartcards so that it could show information to the user. So that the system tray icon could blink when a netkey card with a nullpin is inserted.
With Gpg4win-3 I have removed that feature. But now the user has to actively trigger a GUI refresh when a Smartcard is inserted or removed.
To have a general way to get notifications from the GnuPG System would be a very nice feature and it could be used for that in the beginning.