For me its the fact they're like m-Tickets, rather than e-Tickets. If you got a PDF and you could add it to Google Pay I'd probably choose it rather than a plastic one, but unfortunately while Railcards are stuck in an unreliable app, and have silly restrictions like it having to be opened with an internet connection every 72 hours they're just not suitable for me. Particularly because of the risk of prosecution associated with not being able to show a railcard, if I can't have an offline format which isn't reliant on a 3rd party service then I'm not going to choose the digital option until I'm forced to (or the unlikely event it gets fixed).In what way are they problematic? I have an electronic railcard and have no difficulty. Why would I want to rely on piece of cardboard or plastic which I may or may not have with me at a given time and, if I chose to always have with me, would be just more clutter in my wallet?
I pay for my shopping in supermarkets by phone, my Clubcard and similar items are on my phone. I access my bank account by phone. If I use a bus my ticket is on my phone. Why would I uniquely want a piece of card or plastic for a railcard?
Whether the trade off is worth it is personal opinion, as someone who always carries a wallet (for backup/cards that can't be used with GPay) then the benefit of having the railcard on my phone doesn't outweigh the risk especially without the inconvinience of it being in a different app to my tickets, but for someone who prefers not to carry a wallet then I can see it being a different matter