I'm not Cloudflare, I just read their blog too much. As they hint in the article when mentioning secure boot, they've been deploying Ampere in parallel to AMD for several years now. Purpose wise it seems to be Edge related for efficiency reasons, but maybe they use them for other things too. You can read some more here https://blog.cloudflare.com/designing-edge-servers-with-arm-... and here https://blog.cloudflare.com/arms-race-ampere-altra-takes-on-... along with the original evaluation of Qualcomm here https://blog.cloudflare.com/arm-takes-wing/
Yeah but those are pretty dated. I was under the impression those old Ampere servers are not efficient compared to modern EPYC anymore. So I’m wondering what their current generation of arm64 servers look like :p