The latency adds up. I always complain about Spectrum latency being 30-35ms round trip. PON fiber typically brings that down to 10ms or less.
That adds up when you can shave 25ms off of every DNS query/response, every TCP handshake, every TLS negotiation, and every HTTP resource request. If you can reclaim 25ms RTT, that would reduce every modern web request by at least 200ms. And with all the libraries and CDN resources that modern sites use, often dozens, that can add up to several seconds.
