1) The credits? That's not the point. This isn't a hail mary hoping someone discovers you via rolling credits. It's a way of solidifying your role in this production - so that if someone double checks, did you really help in this production, you are accounted for.

2) Could be useful for future business. It's a display of authority if positioned right. Just like any good portfolio piece.

3,4) Then don't take the contract.

With any business, you are trying to project trust, authority, quality. You could leverage this as such.