I agree there's little direct credit given for developing software, but it can be helpful for early-career researchers to gain name recognition. Even if nobody knows your actual work, if you wrote some software lots of people use, it makes people feel like they know you from somewhere.
Admittedly, it's tricky to do, since that name recognition only really matters if you can also manage to publish enough papers. Realistically grad school is more likely for that than during a postdoc or as an assistant professor. Some grad students manage to release some widely used software (well, usually "widely" in a particular niche), which I think does help them build up more prominence than someone in their career stage might otherwise have had.
On a different angle, having produced some reasonably decent software can be a nice thing to have in your back pocket if you ever consider moving to industry. Having N papers and one decent software package is probably a better academia-to-industry transition CV than N+2 papers and no software packages.
I agree that producing a piece of software many people use is great for your career. I think, on average, most software is never downloaded or used. So, given this prior, is it a good investment of my time to flesh-out documentation and examples rather than just enough to get it published?
Admittedly, it's tricky to do, since that name recognition only really matters if you can also manage to publish enough papers. Realistically grad school is more likely for that than during a postdoc or as an assistant professor. Some grad students manage to release some widely used software (well, usually "widely" in a particular niche), which I think does help them build up more prominence than someone in their career stage might otherwise have had.
On a different angle, having produced some reasonably decent software can be a nice thing to have in your back pocket if you ever consider moving to industry. Having N papers and one decent software package is probably a better academia-to-industry transition CV than N+2 papers and no software packages.