Its been running over here for some time now with minimal issues as users get used to the system. Yes initially people were having issues with the wrong card being charged and even inadvertent billing as someone got too close to a terminal :/ But its starting to become ubiquitous now with minimal reports of issues (the old signature verification system hardly took a criminal mastermind to abuse).
As an example I had a slot in my phone sleeve for the card I generally use for small transactions (akin to the default card you'd set for Apple Pay). I just tap that instead of my wallet. If I want to use a different card I take it out of my wallet (akin to you selecting a different card on your phone). The process is hardly more onerous then you describe for usage of Apple Pay.
WRT security, in Europe the transaction size is limited (£20 in UK). Plus only a certain number of contactless payments will go through before a CHIP and PIN transaction is forced. Therefore it limits the value of targeting the system to thieves and the bank will cover you.
I don't think Apple Pay, or mobile phone NFC payments provide a compelling USP over NFC enabled plastic with the current usage scenario. As I said before, its hardly easier to tap your phone then your CC. And to use my phone I have to setup Google Wallet/Apple Pay first.
However, its the authentication portion of Apple Pay that presents a possible game changer IMO. Since these transactions are authenticated by your finger print we may see limits raised or removed. Moreover, it makes my PIN and card more secure. The card never enters the merchants terminal (as it would have to for a Chip and PIN transaction). My PIN doesn't have to be entered on the terminal (limiting opportunities for people to get my PIN). Fewer people see my card details and I can actually consider leaving supplementary cards at home, meaning a lot less hassle if someone lifts my wallet.
Wether things will play out in this way is another question. I had some hopes for Passbook, but so far its been very disappointing