Like the old Sears Roebuck catalog (good, better, best) I think some temp control is good, ambient temp control in an enclosed chamber is better. I agree that internal temp is best. It seems to me that maintaining a precise zero change internal temp would be difficult with the mass changing on its own and the cooler/heater scrambling to keep up. There has to be some temp fluctuations.
This is why I generally target the ambient temperature in my chamber to be 4-5 degrees below ideal target for the yeast and profile I'm going for during active primary fermentation. Then as things slow down I'll generally bump up the ambient temperature to approach the target for the beer.
I think that's a good practice, especially when compared to just having it in a spare bedroom that fluctuates temp between 55° to 75° lol.