It's a NEW browser in every sense of the word - a new rendering and JS engine, not built on top of Chromium's (or Firefox's) backends. It's impressive because most people have a few preconceived notions: a) It is impossible to build a NEW browser given the complexity and huge history, b) browsers need to rely on JIT and other tricks. This browser is new hobby project, from scratch, breaks away from the preconceived notions of what a browser should be, and gives a glimpse of a future where another open-source project has some influence in web standards instead of the monolith companies that we have now (this is a pipe-dream of course, but we're in a better position now than we were a year ago).

Edit: And I would say to others, please don't downvote a question because I think it was genuine and not meant with malice - and provides a good learning opportunity for EVERYONE