In any event, I hardly know anyone other than the odd private pilot and his mates that are using it anyway.
That is very true. Even in GA there are more aircraft than not which wouldn't show up in any case. The vast majority of CPL students on NAV ex flights won't be using tablets so they won't show up. Many private pilots don't use them, and depending on your organization, a lot of GA charter pilots don't use them.
It would be far more useful to have live SSR and ADSB feeds being downloadable to these apps as it is on websites like flightaware.