It saves a reading of every method's profit once an hour, so you can see how things move over time. The public site can't do that, so trends only work when you run the site on your own machine.
Start the helper, then hit Refresh.
powershell -File backend/start-local.ps1 -Mode api127.0.0.1:8788), then Refresh this page.With only a day or two of history so far, the 7d and 30d views will look thin or empty. That's expected, not a bug. They fill in as more readings pile up.