Description of the need
One on of the Backdrop websites a customer wanted to see e-mail addresses of users without taking an additional step (going to Edit tab).
Unfortunately, there was no option on /admin/config/people/manage/display/default to make the field appear on the View page, but it was fairly easy to satisfy such a requirement by implementing a custom template. However, I still wondered why such an option is not available via UI.
Proposed solution
I'm totally ok if it is by special design not to make the value of e-mail address field available on the View page, however if the community members would share my curiosity why it could not be made available, then this feature request could have a chance.
Recent comments
You can use this module: https://backdropcms.org/project/search_api_block
Search Api form in header?
Have you looked at the BG Image Formatter https://github.com/backdrop-contrib/bg_image_formatter
How to access node fields in block template files
You could also try Current Content Display Block which with a bit of config and CSS could get you what you need.
How to access node fields in block template files