edit is useful and there are good reasons to use it, 'never use edit' is like 'never use goto' i.e. false - but if you're just starting out, jj new/jj squash is the way to go indeed.

(my particular favorite reasons to use jj edit are git-native tools which expect to work with uncommitted files e.g. autoformatters, linters, etc. which have been scripted in CI/dev workflows such that they cannot accept a list of files as params)