That was at the underground Victoria station ticket counter.
That's only for registered cards. Which makes perfect sense, because they're registered to an address to prevent people stealing them and returning them for cash
Bitcoin is already this way. All "cash" is associated with an address. To use that cash you need to be the owner of that address.
note: lose as in someone steals it.If it's totally lost the money is gone, as we know.
You don't have to register your card. If it is unregistered and someone steals it there is nothing you can do to recover any money on the card.
You can choose to register it, in which case you can transfer the balance to a new card in the case it is lost or stolen.
The rare user might prefer to buy Exactly One (or two or four) tickets, as they know they won't use the excess. This is similar to the frustration of a first-time user at the bay area ferries, where the process of registration, app installation, etc, is much less convenient than most parking.
The regular user, however, doesn't care as much about the initial overhead, as the convenience outweighs the overhead. A remainder balance on the card is less frustrating than for a tourist, as they know they're going to fill it up again.
That said, it would have been nicer if the transit company had phrased pricing in terms of Number Of Rides, rather than dollars (dollar amounts made up):
4 rides ($10.42)
10 rides ($21.37)
50 rides ($90)
100 rides ($180)So I assumed I'd need a "tourist" Oyster as I wasn't a resident. But when I looked in to it as a tourist you had to book well in advance so they can post a card to you - whilst if you ignore the "tourist" offering you can just pick up the card at your arrival station (Victoria for me, very easy, was from a machine IIRC). Also the charges seemed higher for tourists somehow and there seemed to be difficulties giving the card back and getting a refund - I could see no reason to have a tourist Oyster.
One of the kids travelled free, with me, as it happened which was great. The only problem is that the automated turnstiles wouldn't let us through separately without us paying twice (for which we'd need a different Oyster) and I got "munched" on a couple of occasions one of which gave me a very sore back, it was quite vicious.
Traveller beware!