I purchased a couple of tourist Oyster cards with £10 of credit directly from
TFL a few months ago for a recent trip to London. The cards worked fine and
aside from all the weekend shutdowns, we had no problem getting around on the
tube.

Just out of curiosity, I registered one of the cards to see the remaining
balance and journey history. However, when I go to the history tab, I get the
following message:

Please note, customers will only be able to view this information if they have
purchased pay as you go credit (including Auto top-up) from Oyster online.

Not sure why this would have to be the case. Purchasing credit from Oyster
online is a bit problamatic as the site does not take credit cards issued
outside the UK. And if I was able to purchase credit, would it only show trips
from that point forward?