The problem with these smaller webbrowsers is that you have nobody to sue if the browser turns out to leak your personal information or credentials etc. Therefore it is better to stick with browsers made by big corporations.
On the (long) odds that you get all the way to a successful class-action suit, the lawyers get rich, and the class members eventually end up with a free year of credit monitoring
(we have seen this over and over again in settlements for high-profile data breaches)