I similarly don’t get the enormous popularity of Carbon but it offers two things that a screenshot doesn’t:
• It frames the code properly; this is an aesthetic choice, and certainly subjective, but many people seem to prefer it. At the very least, it provides consistent, even margins around the code which are fiddly to achieve with a screenshot.
• If you paste a normal PNG screenshot on Twitter, it gets converted to JPEG and downsampled, creating ugly block artefacts around the text and changing the colours. You can avoid this by making at least one pixel of the PNG partially transparent. Carbon does this automatically (but you can of course do it manually with a screenshot).
• It frames the code properly; this is an aesthetic choice, and certainly subjective, but many people seem to prefer it. At the very least, it provides consistent, even margins around the code which are fiddly to achieve with a screenshot.
• If you paste a normal PNG screenshot on Twitter, it gets converted to JPEG and downsampled, creating ugly block artefacts around the text and changing the colours. You can avoid this by making at least one pixel of the PNG partially transparent. Carbon does this automatically (but you can of course do it manually with a screenshot).