If you're worried about tracking, you can block ads and tracking scripts without disabling javascript. If you're worried about viruses, well, all I can say there is that in my experience and understanding, if you keep your browser updated, the odds of getting a virus via browser JS are exceedingly low. Doubly so if you're not frequenting sketchy sites.
I don't know, it seems to me like advice from a time before security was a priority for browser makers, and high-quality ad blockers existed. At this point, I really don't see the value.
Not to mention that a host of vulnerabilities were image related a few years back (one of the original rookits exploited a TGA bug).
> uBlock Origin
Honestly, this is the antivirus of the web. I helped my niece set up my old computer for Minecraft today, and she was explaining how her friend had installed viruses (adware, really) 3 times. Every one of those instances was caused by download link confusion for Minecraft mods. Disabling JavaScript isn't going to save you from being tricked into downloading shady software, only an adblocker will.
Brave's browser claims a speedup over AdBlock plus, but was inspired by UBO, so the performance is fairly similar, but is baked into the browser instead of being an extension.
> We therefore rebuilt our ad-blocker taking inspiration from uBlock Origin and Ghostery’s ad-blocker approach.
Also just so you know, Brave isn't "written" in Rust alone, it is a big software with a lot of parts, including but not limited to a rendering engine, a JS VM and a WASM engine.
The Rust part at most (unconfirmed) would be the glue that connects them together, and I doubt that's where the bottleneck is for most browsers.