Some offers aren't worth chasing. A few quid to avoid Trip and Trainpal is worth it for me.
Trip.com and TrainPal are good at getting you trapped into using their app. The user experience isn’t the best. Lots of adverts, takes ages to load, overall not fun.
I’d stick to the “Railcard” app and swallow the extra couple of quid in the upfront cost.
Despite the fact I should know better, I've obstinately persisted with buying my Railcard from
Trip.com for the past I think three years - I allow myself to get sucked in by the discounted price, then later gently (or not so gently) chastise myself for having done so when trying to open up and navigate to display the Railcard through the myriad of nonsense the app jangles in front of you!
So with that experience I can say that I wouldn't recommend it, well in fact I'll just straight up say I don't recommend it - and
TrainPal is a sister company of
Trip.com and their app is similarly cr@p. All I can say in my defence is that I've never bought anything else from Trip.com (apart from an ultra-cheap train ticket so as to 'activate' the discounted Railcard purchase - said ticket being pettily fulfilled by and collected by TOD so as to inflict maximum financial detriment to them!).
The 'official', standalone Railcard app has had it's issues over the years (though nothing of late I don't think?). I don't recall coming across any reports of trouble with Digital Railcards purchased from and displayed within the Trainline app, ditto the TrainSplit app (the latter being the one I should really be using for my Railcard!).