http3 has enhancements that speed up initial handshakes for new connections (QUIC essentially is UDP plus combining TLS and a native reliability layer to repla

http3 has enhancements that speed up initial handshakes for new connections (QUIC essentially is UDP plus combining TLS and a native reliability layer to replace separate initial SYNs for them separately). So when you go to a page with tons of ads/trackers/javascript libraries, you're not left waiting as long for the ads to serve while browser reaches out to all those components and does separate TCP, TLS, and HTTP connections. But users of most other websites won't see a ton of noticable benefits unless they have facebook/netflix/google levels of traffic. And at that point, you're either highly focused on the end user component code or you've outsourced it to a CDN that'll do the http3 for you anyways.