You shouldn't be able to apply in an MR tho, unless is some playground account. Developers shouldn't have enough permissions to modify production infra from a MR.
Organizations have different rules around when to apply a change. Some prefer to do it pre-merge, that way if something goes wrong they can modify it and apply again, and others prefer to do it post-merge. We are not opinionated own when a customer does it, we just have rules to make sure a change is both merged and applied. Additionally, who can perform an apply is a different, but related, question to when.
The bet behind Terrateam is that a lot of developers and SREs don't want to leave their MR page when applying and planning so we are supporting as much functionality as possible there.
