Install Windows 10 on MacBook Pro 2017 (14,1)
BootCamp assistant is just a utility to make it easier to install Windows on a Mac.

It packages the Windows installer onto a Thumbdrive and slipstreams the drivers to support Apple hardware into the installation so you don't have any non-working devices during boot. It also presents a nice simple GUI to re-partition your HD/SSD.

If you are comfortable installing the necessary drivers (at least keyboard and trackpad/mouse) into a bootable Windows 10 installer then I say, "Go for it."

But I do Windows support for a living and I don't bother with that and frankly don't know HOW to do that. Honestly you are better off just using BootCamp assistant, it is easy and practically foolproof.