One use of this is to send yourself a notification any time you get a response to a google form, since google forms populate a spreadsheet. So you can set up emails to trigger any time a row is added to this spreadsheet. Not sure if there's a better way to achieve this workflow, but that's how I was doing it for years.
Google Form -> Google Sheets -> Email on new entry, is a great way to do contact forms on a static site as well. It's quite easy to customize the look of any Google form.
