Why doesn't Pokémon Go connect to my Google Account when I log in?

I've tried to find similar questions but I don't think they're exactly the same issue I'm having.

When I start the app, I am able to select the Google Login where it briefly shades the screen black and loads and eventually starts to load the game. However, it doesn't give the typical Google Play Games dialogue window where it asks for you to sign into the game - Pokémon Go does not appear to be a connected app in my Google Account. I was able to create a username and start the game, but I cannot find any evidence that my account has actually connected to my Google Account. Uninstalling the game and relogging in brings me my correct Pokémon Go username but I cannot see it listed as a connected app. Any ideas on how to get to "connect" if it actually already hasn't, or is this supposed to happen?

Android 6.0 Marshmellow, Xperia XA.

Ireland, official download from the Google Play Store.

As far as I know (I don't have a source other than personal observations), Pokemon GO doesn't access your Google account at all.

When you "log in with Google", the game checks whether a Google account is present on the phone and what the associated e-mail address is, then loads the Pokemon GO account identified by this e-mail address, without ever trying to access or otherwise use the Google account. It has a completely seperate account based on your Google account's e-mail address, which is the only thing it needs to load that account, operating under the assumption that the Google account would only be present on the phone if you had the password.

Therefore, Pokemon GO will never show up as a connected app in your Google settings. You can't revoke access because all it ever needs is the name of the Google account linked to the device and you really can't hide that from an app. (Also why would you?)

This also means that should Niantic ever shut down their servers, everything Pokemon GO related will be gone, there will be no way to get any records pulled out from your Google account. If someone subsequently created a fanmade clone of Pokemon GO, everyone would have to start over from scratch, it would be impossible to pull any account info from Google or Trainer Club because there's nothing there. This is notably different with games that actually connect to Google, those store settings and usually progress in the Google account and if they discontinue the service, someone can just take over.