Nice to see you review after extended usage. I’ve also worn mine since it came out in 2015, and I have a different experience to you. I also live in London, and find that I’m using Apple Pay on the watch all day every day, from tube, train, bus to buying lunch/coffee or even petrol. I’ve never had an issue myself, and I don’t see it slowing down a queue, vs pulling your wallet out of your inside pocket, and taking out the card you wish to use. With regard to email, I use it regularly to respond to messages, and I use Outlook on the watch to respond by voice using Siri to emails, which is remarkably accurate. Finally, I think the Apple watch would do well to add cellular connectivity (i.e. like the 3G e-sim version of the Samsung Gear S2 in the USA), so that you can still be connected without needing to be tethered to your phone all day.