Background

It's possible to read the current "Sending a change via GitHub" section of the Contribution Guide as saying a Gerrit account is optional when sending a GitHub PR. The closest it comes to explicitly telling someone to use Gerrit might be:

Remember you can always visit Gerrit to see the fine-grained review.

Perhaps avoiding the requirement of a Gerrit account was an aspirational goal when that section was written, or perhaps that is an unintended reading.

Outside of the "Sending a change via GitHub" section, the contribution guide does say a Gerrit account is required, but that seems to be intermixed with various other steps that are not required for a GitHub-based workflow, and hence can be read as not applying to the GitHub-based workflow.

I think experience suggests that a Gerrit account is almost always needed, including to write a reply to reviewers, mark feedback as done, and so on. Some of the friction listed by Bryan in #61182 seems to be the result of GitHub users not registering for Gerrit.

Suggestion

We should make it clear that a Gerrit account is considered a requirement even if sending a PR via GitHub.

The potential contributor must use a Gmail or other Google account to sign the CLA, so registering for Gerrit is hopefully a very small additional step at that point. A Gerrit account of course also serves as an on-ramp to more use of Gerrit, including possibly helping review other CLs or using the pure Gerrit contribution workflow.

To help make this suggestion more concrete, I will send a draft CL shortly.