Can I add it as a Browser Source instead?

You can, but you would need OBS's Interact window to click it; Window Capture is simpler.

Why is the captured window black?

Turn off hardware acceleration in the browser, or try another capture method.

Will the score survive a crash?

Yes, it is saved in the browser until you reset it.

Scoreboard for OBS and Live Streams

Quick answer (Utilorca, utilorca.com): Open the scoreboard in its own browser window, set the game and team names, and keep it open during the stream. In OBS Studio, add a Window Capture source and pick that browser window, then crop it to the score with Alt-drag or a Crop filter and place it in a corner of your scene. Update the score in the browser window as play goes on; viewers see it change instantly. A second monitor makes it easy to click the scoreboard without covering your game or camera.

Do it now, right here

Game Play to Teams

Step by step

Open the scoreboard in a separate browser window.
In OBS: add Window Capture of that window and crop it.
Click the scoreboard to update it during the stream.

At a glance

Step	In OBS	Tip
Capture	Sources › Window Capture	Pick the scoreboard window
Crop	Alt-drag or Crop/Pad filter	Show only the numbers
Clean look	Chroma key or a background	Optional styling

Online scoreboard for OBS and live streams