@Krystof - It depends on what your expectations are of the Google Drive app.
With the app installed, you get a basic document selection window in the Miro interface:
Which displays:
And when you select a document/sheet/etc., they display on the board, but open in a modal window:
However, a while back there was a change where now you don’t even need to install the Google Drive app Miro app in order to embed a Google Drive doc in a Miro board - you can just copy-paste the link from the Google Drive onto the board and the doc embeds the same as if you had used the app to browse to it - the app appears to just be a file browser of sorts.