There is one reason to run Oracle on Google Cloud Platform, one solid and compelling reason. It has nothing to do with cost, and it has nothing to do with performance.
In all fairness, you can get cost savings (or not) with any of cloud provider in terms of software and hardware. But if you are or have to run Oracle, then probably cost is not your issue. For me, one differentiating reason is presence of Google Big Query in GCP.
A serverless, fastest, easiest and very powerful data warehouse GCP BQ is an attraction of its own if you compare it to other competing cloud offerings. I am observing more and more companies drawing to GCP just to use BQ as unified warehouse of their data. Companies are using ETL, ELT tools and flows to push data into BQ from all sorts of databases and data stores on AWS, OCI and Azure.
So if you have a choice, then why not put your Oracle database on GCP VM using their bare metal? If you even mention that to your GCP sales rep, very strong chances are that he will get a very good discount for you. Be sure to mention that you intend to integrate other GCP services with that Oracle database in the future and you might get bare metal for free. That's my guess, but there is no harm in trying.