I agree with you. The tone is most important and if the wife knows how much he loves her then aap ya tum bhool ghar, pyar kam nehi ho jaye gha.
BUT it does something to me when I hear a man say : “Aysha aap 2 min khe liye idher aaye ghi?” than “Aysha tum idher aao ghi?”.
I think it’s like an icing on the cake. The extra respect is shown and by my opinion it’s awesome.