CDC is under Trump, not Congress.
Travel bans reduce transparency and cooperation from the county you are banning, so that has to be considered as well. If countries know your response is to block people from traveling from their country, what is their incentive to share early information about outbreaks? Trump’s feeble mind is simply incapable of thinking more than 1 step into the future.
Unfortunately, Trump is a one trick pony. Travel bans are his tool for everything, but they don’t solve all problems. They may have delayed the outbreak, but the time that was bought was completely wasted by incompetence.