Why does SOCKS5 require to relay UDP over UDP?

Question

The SOCKS5 protocol, described by RFC1928 provides support for UDP.

To summarize, a client wishing to relay UDP packets through a SOCKS5 server must, at least:

Answer 1

I am answering to my own question: it's probably to avoid TCP mechanisms (packet retransmission, head-of-line blocking…).

For a local reverse tethering tool, it is not a problem though, so I implemented UDP over TCP without using SOCKS.