> market share
I'm not sure how popular Brave browser is but it will give Brave search a built in audience when it launches. I've never used Brave. Everytime I've looked at their website, something makes me cautious. I'm a bit cautious about this search engine announcement too, because it takes a long time to build a useful sized index by crawling and then you have the whole ranking thing. But if they can do it I'll rejoice in their good fortune.
To me it's all about having a healthier web. Back before Google when we had 6 or 8 search engines I could get some of my pages ranking in about half the engines (I never could get all of them) and still get traffic. I'd like to see the web get back to 5 or 6 indexing search engines at a minimum because Google is going to continue to hog most of the serps above the fold for their own pages. It might be a pain in the a##, but multiple major search engines is better for SEO in the long run.