You’ll need to evaluate GCP’s peripheral offerings for database, APIs, pricing, etc.

The biggest thing that this does is give you first class access to the ecosystem APIs and with native setups for AppEngine (Heroku-ish), Compute Engine (do it yourself on a VM) and a provider in Gigalixir which runs on GCP that gives a Heroku-like experience but is tailored specifically to everything Elixir needs (hot loading, clustering out of the box, etc).

Between those two things, GCP is pretty strong.