This is a questionable technical choice, especially considering HN's status as the SaaS mecca. So it begs the question: Why?
If the goal is to be able to rapidly switch to cloudflare when under attack then surely a TTL of 600 or 60 would be sufficient whilst being more respectful of your visitors?
It’s not a questionable technical choice (imho) based on the use case. Simplicity is the ultimate sophistication.