The difference between implicit conversion and explicit is just syntactic sugar: do you have to put some visible tokens into the code to allow a conversion to happen, or not.

Implicit conversion can be seen as the compiler deciding among several possible conversions (or possibly just one) and inserting the coercion/casting operator into the intermediate code to make it happen.

(Of course, this can be a run-time decision based on dynamic types also, but the reasoning is the same. E.g. the run-time sees that a plus operation is adding an integer and float, and can either signal an error (requiring the program to be repaired by inserting a conversion operation into the expression), or just do that conversion, like the integer operand to float.