What problem does this address?

The search block comes with a number of easily configurable defaults:

Including:

• It's resizable
• Label can be toggled
• Button can be an icon button
• Button can be toggled off, shown outside, or shown inside

One nice addition would be the ability to show only the icon.

What is your proposed solution?

Add an option to show just the search button:

On focus the input field would then expand to allow search.