Primary partitions not being available is pretty much irrelevant here. You'll have to get a warning either way, your system may still be using UEFI, or you might move the disk to a UEFI system and it would stop working, so you need to be notified about that.
Improving messages is 1983719
Primary partitions not being available is pretty much irrelevant here. You'll have to get a warning either way, your system may still be using UEFI, or you might move the disk to a UEFI system and it would stop working, so you need to be notified about that.