Jantango: I appreciate your comment. You are very right, and that's one advantage of BA vs. Japan, but I often need to make and receive calls while I am just around, or using Google maps for whatever, and having a pocket wifi is super convenient.
Ries: thanks for your reply too. I assumed there was a cost in addition to the equipment, but I was not aware it could be that expensive. In Japan, it is very hard to find wifi in coffee shops, etc. and so many tourists and locals use these pocket wifis (you can rent them for short time periods) , so I assumed they were low cost. What was not clear in my mind was whether I could rent one in the US and use in Argentina. I just loved their convenience; lots of airbnb's in Japan advertise that they give you a free pocket wifi during your stay and it's a strong inducement.
Thanks again all for your responses.