I would prefer to use my Android phone, with "Google Pay" to pay for train, tube, and bus travel. I am reading conflicting posts as to if it makes any difference which credit card is being used by Google Pay. I prefer a Master Card, but I'll need a secondary card as well. I've read that American Express is a problem. Also, my spouse will use her iPhone, and "Apple Pay" with the Master Card. If it makes any difference, my Master Card does have a chip, and I've set it up with a pin number, although in France and Italy in 2017, I don't recall using the pin at all.
Anyone with practical experience?
Thank you.