Describe the bug
When testing the Search block, I was going through all the options and found that the button only option doesn't have any action tied to it. It doesn't do anything as it doesn't have a search term to look for. It just reloads the same page.

See also comment #24666 (comment)

To reproduce
Steps to reproduce the behavior:

1. Add a search block
2. Select the "Button only" option
3. Save & preview
4. click on the Search button.

Expected behavior
I don't think there is an expected behavior. The "Button only" option feels foreign to the search functionality, unless an additional action is tied to it.

I can imagine for instance, a form field to slide out on button click for a visitor to enter a search term and on the second click it initiates the search. Describing it still feels a bit awkward, though.

Screenshots

Editor version (please complete the following information):

• WordPress version: WordPress 5.6-RC1-49694

Desktop (please complete the following information):

• OS: 19.15.7
• Browser: Chrome
• Version 87.0.4280.67