I am visiting Berlin at the moment, and I miss the convenience and speed of being able to pay with contactless, by card or phone.

Regarding the speed of transactions: cash might be faster than signature or even Chip+PIN, but is surely not faster than contactless.

For example, anyone with a contactless Visa/Mastercard or phone can enter the London Underground by simply tapping at the barrier. They do not need to have a pre-existing relationship with Transport for London, to buy a ticket in advance, or to preload a stored-value card (as you generally must do in other city transport networks). And the ticket barriers open on average in 480ms. [1] That's pretty fast. You can't even pay by cash on a bus in London any more.

[1] https://www.whatdotheyknow.com/request/payment_methods_time_...