But it happens all the time with other languages. Especially when that language is newer or in the headlines. NodeJS/Electron was a big one a few years ago. Ruby/On Rails a while before that, have seen it for python programs and way back in the day when java was all the rage.

Personally I think it does matter and as a end user I do care to come degree. It tells you some things about the program, like how it can be install/run what deps you might need, is it going to be a memory hog or possibly full of vulnerabilities. The language affects all of these things, more so when the projects are new or niche and have not been hardened over time or been properly packaged yet.

Personally I love it when a program is written in languages like rust or go as it means I know it is going to be easy to build/install and distribute given they build into single binaries and very easy to make static. But if I see one written in nodejs with electron I am disappointed as I know it is going to be a huge package that consumes large amounts of memory. Or if there is some python package that is not already packaged by my distro I would avoid it as I hate dealing with python dependencies and its virtualenvs.

And for this case, with redox. Well redox is not an application to be used by people. It is a showcase about what can be done in the language. It is not intended for most people that hear of it to ever run it or even want to run it. Yet is very impressive what they have managed to do in it. Including having parts written for it be able to work standalone in Linux and other OSs.