On January 3, GitHub introduced a new feature: Issue Types.
These are now turned on for the python organizations, and in the cpython repository they duplicate existing type-* labels.
Since existing issues use labels, that’s what one needs to use for searching. To make label searches work, labels need to be used on new issues as well (optionally with a redundant type).
I see no advantage of using issue types over labels yet.
I suspect that means it’s going to be a poor fit for orgs like ours where lots of different kinds of projects are hosted under the same org.
If there’s enough commercial demand for allowing the available issue types to vary by repo, there might eventually be more flexibility on that front, at which point it could be worth revisiting the question.