Not for long. Yes, they'll generate a lot of temperature, but not a lot of BTUs. Meaning, you get localized heat, but not enough to raise the temp of the whole system of fluid. And they'd likely lose torque capacity before long anyway.
@pnora provided the best info. 'To cooler' will be the hottest location to measure, as the fluid in the converter is the hottest part of the trans.
Temperature monitoring in the cooler circuits is for diagnosis. Sump temperature is the good-health monitor for a system that is designed/known to work properly.
FWIW, I would never run without the liquid-liquid cooler in the radiator, as it provides a lot of stability to the trans fluid temp.
It can help warm the trans up when cold, and can pull a lot of BTUs from the converter-out fluid.
If more cooling is desired, then yes, an aux cooler is a good addition.
And contrary to sayings like 'get the biggest cooler you can fit' or 'get the fluid as cool as possible' - don't.
Get a cooler that will help keep your fluid in its designed temperature range.
And - don't use copper in any automotive fluid tubin more easily than steel.g. It work-hardens from vibration and will crack