Why is FCP still being shown in field data?

Although not being part of Core Web Vitals, you still see FCP being displayed in the CrUX or field data, when:

• your site or shop has enough visitors;
• you are checking PageSpeed Insights or Google Search Console data.

Reasons might be:

• esthetics, 4 graphs is easier to divide over two columns than 3 graphs;
• FCP still is the first noticeable metric after TTFB. TTFB is important, but FCP can still be pushed back depending on your theme or frontend code. As a results, FCP still gives you a good understanding of first user engagement. A white screen for a long period could increase bounce, so you might want to keep FCP (and still engaging with meaningful elements) as low as possible.