My guess is Wall Street HFT or other financial areas with very strict unscheduled downtime penalties where they are effectively incentivised to be batshit paranoid as it would take decades for any penny pinching to remotely pay off. I don't know if many of them use Cloudflare for their domains though.

There’s a lot of truth to this. Cloudflare for now has achieved IBM status in that no one will be fired for choosing Cloudflare, in spite of any issues that arise.