Using Python how frequently?
The issue is the frequency. Due to not coding in it often, you don't retain it.
> Using Python how frequently?
Probably around once a week.
A linter should make you a better coder, whether or not you code frequently, and also serves as a secondary "belt and suspender" check for code sanity and ease of future reading/refactoring.
Once you get used to using shellcheck all the time your code style starts to match what it requires. You start thinking about quoting and other intricacies, and coding much more defensively.
This happens with other checkers as well - >90%+ of the time the python I write passes pep8 and black cleanly after having used those tools for a year or two.