for some it takes a little more time to come up to speed with new tech, including the ebay app, which has limited capabilities

If they don't know how to use it properly then they should probably not use it until they learn how.. Particularly when they're wasting the buyers time..

IF they know the app can't do some things, then go and find a PC..

I find the App works fine for me, but I only ever use it for buying and adding things to my watch list.