Real time tele really would be useful especially for some things like rpm and temperature, If you're overheating you could shut down and land and fix the airflow probs before you trash the engine, comes to mind for planes, boats, and helis, esp with cowled in engines and inline engines. Admittedly once a machine is set up you wouldn't use the function alot but this hobby is laden with continual experimentation so I like the possibilities.
Futaba radios should have a soothing female voice, with heavy Japanese accent, to warn you of "Engine Too Hot" or "battawy is Lo" or "Gasoween is lo!"
of course the german-made radios will play WW11 triumphant marches everytime your 1/5 scale me109 lands too.
