docs: explain no-unused-vars advantages over TypeScript (#7347)

* docs: explain no-unused-vars advantages over TypeScript

* Update packages/eslint-plugin/docs/rules/no-unused-vars.md

packages/eslint-plugin/docs/rules/no-unused-vars.md

@@ -8,3 +8,20 @@ description: 'Disallow unused variables.'
 
 This rule extends the base [`eslint/no-unused-vars`](https://eslint.org/docs/rules/no-unused-vars) rule.
 It adds support for TypeScript features, such as types.
+
+## Benefits Over TypeScript
+
+TypeScript provides [`noUnusedLocals`](https://www.typescriptlang.org/tsconfig#noUnusedLocals) and [`noUnusedParameters`](https://www.typescriptlang.org/tsconfig#noUnusedParameters) compiler options that can report errors on unused local variables or parameters, respectively.
+Those compiler options can be convenient to use if you don't want to set up ESLint and typescript-eslint.
+However:
+
+- These lint rules are more configurable than TypeScript's compiler options.
+  - For example, the [`varsIgnorePattern` option](https://eslint.org/docs/latest/rules/no-unused-vars#varsignorepattern) can customize what names are always allowed to be exempted. TypeScript hardcodes its exemptions to names starting with `_`.
+- [ESLint can be configured](https://eslint.org/docs/latest/use/configure/rules) within lines, files, and folders. TypeScript compiler options are linked to their TSConfig file.
+- Many projects configure TypeScript's reported errors to block builds more aggressively than ESLint complaints. Blocking builds on unused variables can be inconvenient.
+
+We generally recommend using `@typescript-eslint/no-unused-vars` to flag unused locals and parameters instead of TypeScript.
+
+:::tip
+Editors such as VS Code will still generally "grey out" unused variables even if `noUnusedLocals` and `noUnusedParameters` are not enabled in a project.
+:::