I mean the feature itself has been vetted, i.e. it wouldn’t be in the language if enough people didn’t find it reasonably useful. TLA is a substantial feature implementation-wise so I expect TC39 to have thought “yeah that’s still worth it”
TLA was accepted in the specification before the module loading scenarios were fully baked. Probably best to use async IIFEs until the TLA spec bugs are sorted out and the fixes are subsequently implemented in the major browsers and released. Maybe a year from now.