Tested this MR.
I removed all content_translation permissions from a given user. They could no longer see the "Translations" tab in that case.
However, when given the "Create AI translation" permission, they could still access the translation URL directly, and a translation was added. Not sure if this is desired behaviour, or if it should be an AND operation: only create AI content translations when you have "create ai content translation" permission + the appropriate content_translation permission as well.
So the original issue raised in this topic was not yet fixed, AFAIK.
The improved logic to hide the AI Translation column when not relevant, seems to work and is definitely an improvement.