Only one reason: Chrome has hands down the best security track record.
Why not use Brave instead, then?
I’m sure it says somewhere but i could not find out what version of chrome(chromium?) brave is based on while trying to find this out for maybe 5 minutes. So, just to be sure i am not installing an browser with known vulnerability I’ll stick with chrome for now.
If you look at README in the repo [1], it says that the Chromium version can be found in `package.json`, currently 90.0.4430.61, released 4 days ago [2].
[1]: https://github.com/brave/brave-browser
[2]: https://github.com/chromium/chromium/releases/tag/90.0.4430....