How necessary are aftermarket gauges in gas motorhome

The 4R100 transmission used with your F53/V10 has a transmission temperature overheat indicator on the end of the shift lever. The light that turns on when the OD is off will flash if the transmission overheats. I don't recall what temperature turns it on though. I installed a dash mounted analog gauge with a sensor in the test port, just as I did on our previous F53/460 E40D tranny equipped coach.