While doing the deployment it happens to have unit tests/smoke tests that are failing.
If they are failing and you did not do another deployment you will not see in the validations that they are failing, the same goes if you fix them, without running again the deployment you are not aware in validations that they are fixed.
I think it will be useful in this case, but also in others, if you fix something that is in validations, to be updated also there.
