That's fair, I haven't tried it on low end/older hardware. I only just found performance good enough in the 46 release so I've only tested on my high and middle end system. I have some n200 hardware arriving soon and I might give it a go on that.

Advanced privacy and security I agree with and that's the main reason I don't use it daily personally. I think better extension support would be a good step in enhancing that even if they keep the base simple. There is also non trivial issues such as fingerprinting which is going to be a lot easier on a browser with so little users.

Firefox does currently have a few more options and I don't see Gnome Web getting that ootb any time soon. Granted half of firefox's options these days is to disable telemetry from Mozilla, the actual user exposed options isn't huge (outside of about:config). Gnome does have gsettings which could serve a similar usage as already seen with enabling web extensions.

I don't think it will be mainstream any time soon not until Linux is or they support other oses. But I want to be optimistic on how it will be for Linux usage especially with the tablet and mobile scene starting to take shape and Gnome Web being one of the most viewport responsive browsers.