Comment # 2 on bug 939453 from Michael Chang

Hi Chris,

The problem is that not all users like the idea to write grub/grub2 to LBA0.
Some of them may prefer toggling the active (in msdos table) or legacy_boot (in
gpt table) flag to boot the partition where grub2's boot.img gets installed to. 

It's an installer feature, and it tries to offer more possible loader
locations.

Thanks.