In general, I’d say that if the translation was done by you and you’ll have someone review it on weblate and vote on the suggestions, then Add as suggestion is best.
We have the project to automatically include any suggestion that gets two votes (submitted + someone else).
If you’re uploading a translation contributed by someone else and you have yourself gone through it, then you can push as Add as translation so that it goes live immediately and doesn’t need you to go vote on the suggestions.