I wonder if this raises questions about privacy, if you're ultimately going to end up in googles eco-system in a way anyway why would you want middleware?
As a cloud provider I really like GCP compared to others.. it's clean, consistent, predictable and easy to use.
Speaking personally in my employment AWS always sent sales folks and Google always sent engineers, this makes me more comfortable too.
Hosting encrypted data in the Google Cloud is not the same as having the Google ecosystem where you willingly let Google harvest your email/history/location/etc.
Apple does then get Google security. They have found most of the big vulnerabilities including Shellshock, Cloudbleed, Heartbleed, Broadpwn among others.
As a cloud provider I really like GCP compared to others.. it's clean, consistent, predictable and easy to use.
Speaking personally in my employment AWS always sent sales folks and Google always sent engineers, this makes me more comfortable too.