MOVE vs ":=" Assignment Operator

This question specifically relates to a Schneider M340 PLC, but I believe it may be applicable to other platforms as well. I am working on new logic in structured text and realized that I have the option to assign one variable to another with the ":=" operator (example x := 3) as well as the "MOVE" instruction (example x := MOVE(3) ). What is the difference with these two techniques?

Effectively the same thing
:= is specifically a structured text instruction, while MOVE is a function available in all languages