- I can use Value with float as easily as with double without explicit type casts anywhere

- Assigning a float to Value reads back from Value exactly the same as it went in

- If EditFloat* is again replaced by EditDouble*, the behavior is exactly the same as it is now with EditFloat*

- float supports Null

Maybe the precision hint you are suggesting could be automatically initialized in Value(double) / Value(float) constructors and assignment operators =(double) / =(float) to suit the assigned data type?

	double x = 3.14159;
	Value json;
	json("pi") = Precision(x, 2); // Precision does not exist yet
	DDUMP(AsJSON(json));

{"pi":3.14}