Why browser-developer Brave launches a version 2 (less secure) own website on the Tor-network?
The address Brave choose = -http://brave5t5rjjg3s6k.onion/
The outdated Tor v2 .onion services protocol (with the short .onion address consisting of a string of 16 characters) will be phased out in the year 2021. Therefore you'd better register the longer v3 .onion addresses ( 56 characters long), when available. Existing v2 onion addresses will function as long as the Tor network support for them will last (ending July 15th of 2021), and then will become obsolete. The newer v3 protocol is much more secure as the previous one was.
(info source: credits for this indo goes to anonymous on Security dot nl)
As humankind's understanding of math and cryptography evolved, the foundation of version 2 became fragile and at this point in time, unsafe. If you want to read more about the technical problems that version 2 faces, please read this post and don't hesitate to ask questions if any.
Read:
https://blog.torproject.org/v2-deprecation-timeline polonus