While we can achieve most improvements with TCP too (assuming you're on linux and have a recent kernel) there are a few things that QUIC offers on top of those

While we can achieve most improvements with TCP too (assuming you're on linux and have a recent kernel) there are a few things that QUIC offers on top of those improvements 0RTT session resumption, while TFO could offer this too most people don't enable it due to broken middleboxes. Header encryption, which hopefully prevents future ossification due to those broken middleboxes. Multiple independent streams within a connection where each stream only suffers from its own packet losses instead of all streams being affected together. This provides a small latency benefit. TCP SACKs and fast retransmits should paper over most of this latency, but not all of it. QUIC also offers more SACK ranges than TCP SACK which might help on links with high, non-bursty packet loss. Then there's path migration, e.g. when switching from mobile to wifi. This could also be achieved with MPTCP, but that's still making its way into the kernel.