Other reasons could be dropped support for older MacBooks, the ability to use a custom/modified Windows installation or if you want to install on an external drive. For example if you want to get completely rid of macOS. Although this does work in a lot of cases, there might be reasons to manually install Windows on your MacBook. The supported method is to use BootCamp Assistant. For quite a long time now, Apple supports running Windows on your x86-based MacBook.
