In fact defederation is a negative since now you have to worry about new signups, moderation, etc. While in a federated instance, you can leave moderation to other instances and only allow team/company members on your instance.

They are going to moderate their communities, if its unfederated, you don’t have to worry about moderating (or the lack of) on any other instances communities at all.

Users can sign up on other instances and still be able to interact with your instance for support, help and other stuff.

Thats going to be too confusing for a lot of users - they just want to sign up and complain about/discuss things.

It depends if they are saying, we have a community on lemmy (federation fine) or saying, here is our official forum thing (federation bad)