OWASP disagrees: See https://cheatsheetseries.owasp.org/cheatsheets/Nodejs_Securi..., listing `eval()` first in its small list of examples of "JavaScript functions that are dangerous and should only be used where necessary or unavoidable". I'm unaware of any such uses, myself. I can't think of any scenario where I couldn't get what I wanted by using some combination of `vm`, the `Function` constructor, and a safe wrapper around `JSON.parse()` to do anything I might have considered doing unsafely with `eval()`. Yes, `eval()` is a blatant red flag and definitely should be avoided.

While there are valid use cases for eval they are so rare that it should be disabled by default and strongly discouraged as a pattern. Only in very rare cases is eval the right choice and even then it will be fraught with risk.

The parent didn't say "there's no legitimate uses of eval", they said "using eval should make people pay more attention." A red flag is a warning. An alert. Not a signal saying "this is 100% no doubt malicious code."

Yes, it's a red flag. Yes, there's legitimate uses. Yes, you should always interrogate evals more closely. All these are true

When is an eval not at least a security "code smell"?

It really is. There are very few proper use-cases for eval.