It's not meant to be a place for developer bios. If for no other reason than one developer could appear in many OWNERS files scattered throughout a repo, or in multiple repos, and keeping the bio current across all of them would be a nightmare.
Let me add some context. I was looking at the governance links on the site and found https://fuchsia.dev/fuchsia-src/contribute/governance/eng_co... which at the bottom simply says "The current members of the Fuchsia Eng Council are listed in this OWNERS file." I think it would improve the transparency/accountability of the project to have more than a list of email addresses here.