Question on Windows 10 Pro Architecture

I see three options when I’m about to install Windows 10:

32 bit
64 bit
and both

is there a reason to select both? it’s around 8GB of data compared to the 64bit, which is around 4

Isn’t this the media creation tool?
I believe it’s asking what installers you want to create, not what you want to install…you can’t install both.