If your opponents says travel in terms of non-long distance, it is to your advantage. How would a walk down a street be more enlightening than by watching a documentary? A documentary is an educational video that has been made and commented by experts, and involve a great number of people. Surely much thought has been put into the process of making it.

Our imagination much or less shapes our mindset.
A person with rich imagination can analyse things much differently compared to someone with lesser.
Before you ever been to a place, you will imagine what is the place looks like, the culture of the place, the type of people that populated that area,.....etc.

Intrigued by Marco Polo vivid although ambiguous description of the culture of the east, the medieval europeans are driven by huge desire of curiosity to unravel the mystery of the orient. With wild imagination, they began to think of many sort of things that go beyond their boundary of normal expectations. Shakespeare never travels outside england much but how can he create some masterpiece out of tales like Julius Caesar or Hamlet for that matter. He never travels much but its his imagination untainted by the actual experience there that he can shape which ever way he wants.

Let's say when you never been to Rome so you will begin to imagine how the place looks like which you will then begin to research as much as possible by going google or travel books. Expectations & imaginations tends to be higher than the actual ones can offer.
If you did travel to Rome & see most of the things that you have already imagined or dreamed first place it will "narrow" your mind to the actual thing or facts. When you imagine the people there will be nice, you realised you dont speak Italian.

I think the keyword is the word "broaden" which you can argue quite effectively. Travelling indeed broaden some of our real life experience but narrows our mindset & imagination to the things at present.