Branding and trust. ML folks love HF, and rightly so. They have great software libraries, host everyone's models, generally great UX all around. They do a great job of making it easy to do cutting edge stuff, while still making it possible to do bleeding edge stuff. They appeal to basically all ML folks in a way few other companies do.

Google could grow GCP by more deeply integrating HF into GCP, I think, while retaining as much of the HF brand and interface as possible.

Big friction point might be ethics, since HF is still seen as the "good guys" and where some folks who left Google over ethical concerns landed.