Anyone remember burning their hands/legs on vinyl car seats in the 70s when they'd been parked out in the sun? That would be far worse on a train as sometimes all the seats along one side would have the same problem - and you couldn't put a blanket over them beforehand!
In terms of viruses, I've read that the current one seems to survive on harder surfaces longer than smoother ones, so I would have expected moquette to be best in this sense.
Easier to effectively sanitise a hard seat, though. So horses for courses.
Nottingham City Transport went for similar leather effect a few years ago but they didn't seem to wear very well and they now have a flat cloth instead.Hard plastic bucket seats - no, no, no!
Some of my local buses now have leather-effect seats (doubt they are real leather), which seem to clean better than moquette, and are just as comfortable as moquette. Sitting on a soiled moquette seat can be quite off-putting, as you are never quite sure what has soiled it. But I doubt that the "leather" is any more virus unfriendly than moquette, as the "leather" is not perfectly smooth.