actually it makes total sense for foreign travelers, who can immediately travel without finding a suitable location to purchase an Oyster card (for 5GBP), worrying about how much balance to put on it (being a tourist, I had no idea) and then waiting in line for over 30 minutes to return it (and get whatever was remaining as a refund) when I was done.

I actually had to do all of these things, because the first set of machines I ran into (and then used to purchase an Oyster card) didn't have signs about being able to use contactless now.. all of those signs were around the corner :-)

London is lucky enough to (at least for the underground) allow cash or EFT fares at the stations, in some hostile cities like Sydney you cannot catch a bus without a pre-purchased multi rider card which you can only buy from certain outlets.. you can not pay cash on board. Combining the inefficiencies of avoiding cash on rides with the global standard of contact less payments makes total sense to me