it has MUCH less access to your phone on GrapheneOS than stock android and can even be limited to only contexts where its required.

plus Graphene still blocks a lot of the other attack vectors that corporations use to track you like Dynamic Code Loading and Memory Tagging. to say installing google play services to your main profile defeats the purpose of GrapheneOS is to ignore like 80% of what GrapheneOS does and how it installs google play services

It'll still try, it just wouldn't have root access. It would just depend on what you allow it access to.

It gives you more control over when and what Google can do on the device. If you run Google software with network access you have to assume they can track you, but having it sandboxed minimizes what it can do while running and gives you more control over what it does (e.g. you can deny it network access entirely whenever you want).