I use an iPhone for many reasons - the payment mechanism is irrelevant beyond the fact that it exists. The express mode feature is there, including the ability to select which card it uses, and as a layman I neither know nor care about the underlying architecture. While Apple meets my needs, I'm also unlikely to move back in future.
My view is very simple. If an operator takes payment by a particular means, it is for the operator to ensure that I am not falsely accused of travelling without paying. A method of inspection cards that cannot accommodate a payment method that the operator has agreed to take, and advertises that it does take, is unacceptably deficient. That is equally true whether it is Apple's implementation of Express Mode, or a failure to print a ticket at a machine. It is fundamentally unacceptable to accuse someone on not paying without evidence to support the accusation, and the inability of inspectors' card readers to identify a normal use case is a long way short of evidence.
I did do this before I discovered the express mode on mine, coincidentally about the time that Apple moved towards facial recognition and away from the thumb lock. But there are many features on my devices that I do not understand well - it's on me to identify how they work. And watching people at barriers, I get no sense that the issues of user familiarity are particularly focused on any OS or manufacturer.
You've obviously never been around as people have fiddled around finding the right card, or trying to deal with a failed magstrip on their ticket. Like
@Starmill, I never usually need to break step with a card payment on my phone; scanning a ticket depends a lot on the state of the barrier.