Regarding MyNumber card

I recently moved to Japan as a temporary resident (for 1 year) and received that red card when I went to the city hall to pay my NHI. A few weeks later, I received a letter saying that IF I wanted a MyNumber card, I'd have to apply for it.

My question is, if I apply, do I need to pay something for it (like NHI)? Is it totally free? I know MyNumber card is good to identity verification (such as opening a JP Bank account).

And last but not least, do I really need it?

by GiveNoFxck