I have not used a tablet with app ect but on cars with built in screens that have gauges you can cycle through they are not always accurate.
Issues appear to be due to sampling rate. It seems the electronics sample every x milliseconds and use logic to smooth the values, the results are that if for example there is a rapid upward trend which suddenly stops the gauge may continue that upward trend until it takes another reading.
I see this a lot on built in digital boost gauges (not aftermarket purpose built ones) but if it's reading from stock map sensor. People are lime omg I hit 22lbs of boost! And I'll go do a run with an expensive scan tool doing a fast sampling rate or a mechanical gauge and be like nope max was 17psi
Dunno if you'll run into this with a tablet but something to be aware of. Temps probably don't change fast enough to cause these problems if that's what you're after.
Basically if you are talking about something that plugs into the obd port and reads factory gauges probably fine for like coolant temp oil temp ect, but may not be good for like rpm or various pressures.
Also it is hard to watch all your gauges when racing. I mentioned in another thread that we have an alarm that sounds if oil pressure goes below 20psi and others commented that they cannot hear due to car noise and use a flashing light.
If you are talking about like an aftermarket instrument panel for rpm speedo ect, i had one on my motorcycle Years ago and it was great but I forget the brand lol