Its not easy to monetize just on its own obviously.  You'd need
to be running some kind of software-as-a-service business.

To start one for the sole purpose of claiming $20k of free services
would be foolish. 

But since you already have plans for a group communication app,
why not run your services on the cloud there?  You can get
free hosting, DB, whatever you need!

Another option is yeah, just try to sell it to someone who is
using google cloud or plans to.