They do indeed. However there's no way to heat the bottled water in many cabin setups. Therefore when it comes to hot drinks, we the crew are all drinking potable water.
I'd thought that if they were going cashless, they'd at least have the manual backups for card payments. It's basically carbon paper imprints of the cards. It's old school, but it works. I don't think it's acceptable for a long flight to say 'our management send their apologies, and we have cups of free tap water available'.
I do find it amusing. Once upon a time BA crew and pax would look down on the likes of easyJet and their passengers. Fast forward to 2017, and they're easyJet Heathrow. Nothing more.