Many browsers have a special version for USB. For example, when you install Vivaldi or Opera you can choose “Stand-alone”, or you can just download a portable version of Maxthon directly from the official website.
Formally the only reason why people may ask you for an official portable version of your software is the ability to save it on USB and use on any PC. You don’t need to install portable version: it works as a folder.
But for many users portable versions is the simplest way to try new software: if you don’t need to install it, you won’t have any problems with deinstallation. I’m sure if Brave will release official stand-alone version (like Opera and Vivaldi), this will attract many doubting users who aren’t ready to install the new software. It’s simple, but it might work.
For example, now I’m working on too slow laptop and I am not ready to install Brave or other big browsers. But I have already “installed” stand-alone Opera and Maxthon, and maybe I’ll “install” Vivaldi after the next update.