The issue you discovered with the unresponsive button os a bug, thanks for finding it. You can still switch, if you click the checks on the right, I just forgot to attach the text to the click. That will be updated this week.
I want to add a widget at some point, so keep an eye out for it in the future.
The free API basically is just less information. Shorter forecast, 5 vs 8 days, 3 hours vs 48, etc. the details are mostly the same, just essentially looking through a smaller window.