I've seen #4607, but I feel it's important to bring this up again.

I think this decision is quite unfortunate.

Is the expectation that developers will add 'use strict' to their ESM/TS source code when dual-bundling as ESM/CJS? Including 'use strict' in ESM code seems counterproductive.

An alternative might be to add 'use strict' to CJS files by default when "type": "module" is used and bundling for CJS.