[microtonal]

But I thought the point of GrapheneOS was to escape that.

I think the point of GrapheneOS is being as secure as possible first and within those parameters give people the choice how much of Google they want. They have implemented sandboxed Google Play Services for a reason. Many people need Play Services for practical reasons (e.g. because they need to run apps that require it), so let's then run it in the most secure/private way possible - make it a sandboxed app, allowing users to decide whether to install it or not and if they choose to, that they can assign/revoke permissions like any other Android app.