I have a GPU heavy application I'm looking to provide to a set of users that might not have the hardware on hand. Amazon offers AppStream which allows me to stream a particular application via Windows image to users. You can set it to scale (in theory) to as many systems as you'd like, and you have the option to have ready instances or instances on standby (cheaper, but longer to start up) Users log into AppStream and are presented with just the application and are unable to get at the back-end windows infrastructure.
AppStream works perfectly except for the way it interfaces to S3, it can take 10 minutes to upload a file in MB sizes, and they don't seem to be resolving this issue anytime soon.
Does Google offer a similar service?
There is not a specific GCP product that performs the same tasks as Amazon AppStream per their documentation.
You could accomplish the same result with multiple GCP products, for example there is a Citrix solution in GCP in this link (you need to register)