I have no objection to showing an e-ticket on board the train, and always carry a back-up power bank, but my issues are (a) at the gateline when juggling luggage and trying to put my phone against the scanner before the display fades if I'm in a queue, and worrying about dropping the phone if I don't have a dedicated free hand, and (b) I buy tickets occasionally for other people who are not confident with e-tickets, and anyway if the ticket is on my phone it's no use to them.
As mentioned in the other thread I no longer have a printer that is compatible with my laptop, and I'm hesitant to buy a new one in case that too turns out not to be compatible, and also apart from rail tickets I would have virtually no other use for a printer. I have looked on Amazon for printers but they don't say what they are compatible with, and also the reviews for most of them talk of nightmarish installation processes and being over-complicated. I'm underwhelmed that when googling for compatible printers on Apple's website the suggestion is to "contact your printer's manufacture" - yeah right.