It works well in California. Just had one the other morning for a 4.2.
Depending on how far away it is I’ll have a few seconds notice. This one was really close so the alert came in almost at the same time. Last year I had about 10-15 seconds notice for a 6.4.
Disney already wrote off 90% of what was canon at the time and turned it into “legends” when they bought rights. They can do it again.