[jofer]

It's very true that it's not scientific research. (And I actually generally agree with the premise behind "methods shouldn't be publishable -- they're for appendixes, not papers".)

However, there's increasingly a role for folks focused more on the scientific computing and methods side. E.g. "how do we constrain X parameters given Y observations" (yes, I just described inverse theory -- that's deliberate). The science isn't solving the problem, it's figuring out what models to use and what the inverted parameters mean. However, solving the problem correctly requires a lot of rather novel work and is very easy to get wrong.

It's similar to many other research staff positions. It's standard to include the person who operated/designed/etc the instrument you're using as an author on papers. Is it that crazy to include the person who developed the numerical methods and implemented the solution as well? For example, I have quite a few friends that stayed on as staff to run the lab or key pieces of equipment. They have tons of "middle author" publications as a result.

However, numerical methods and computing infrastructure and work is much less frequently recognized. This is a step towards changing that.