Linting helps ensure that our code doesn't have issues that could come from a typo or basic error. All developers make these mistakes from time to time; they aren't caused by a lack of knowledge, but maybe a mistyped keystroke. Linting catches these issues quickly and painlessly for us.
Code style is also very important, especially when working in large teams. If you don't enforce a particular code style across the project, different files will quickly become out of sync. Developers will naturally deviate to their personal style of coding over time if left to their own devices.
In this Coffee Break Course, you'll see how ESLint tackles both of these problems, and tackles them well. It's fast and feature-full, so it's easy to see why it's so insanely popular.