True, but it's still the difference between being able to load all embedded resources from a server close to the user or potentially having to haul all of that across an ocean, considering TCP congestion window scaling (which is sensitive to round trip times) etc.
All that said, based on a purported comment by the maintainer of archive.is, the aim of their CDN is actually not improving responsivity, but delaying legal/law enforcement responses: >>36971650
> Archive says that privacy is preserved because they truncate the PII.
Personally, I don't have a lot of sympathy for either party here:
I think, especially given the comment linked above, Archive's latency/efficiency concerns are just pretext for quite different concerns of their own (having to deal with law enforcement).
And on the other hand, while Cloudflare's EDNS subnet truncation might help user privacy in a few edge cases (as many have said here, the visited site will get the user's IP as soon as they connect to their servers!), it also makes it that much harder for CDNs other than Cloudflare to efficiently serve content using DNS-based routing and forces them to also use Anycast, which is much harder to do.