Disk Management vs DISKPART Partition Differences (Disk Management leaves 1 MB free space)

I've been experimenting with different ways to partition/format an external hard drive. I've noticed Disk Management and DISKPART don't seem to be doing things quite the same. Disk Management will always leave 1 MB (1024 KB) of unallocated space at the end of the drive, and DISKPART doesn't. The general steps I've been using are listed below.

Disk Management
1) Clean drive using diskpart
2) Initialize drive using GPT in Disk Management
3) Create partition using all available space in Disk Management
--There is 1 MB of unallocated space at the end of the drive. (It shows 1024 KB free when using the 'list disk' command in diskpart; and using the extend command in diskpart will claim this space.)

DISKPART
1) clean
2) convert gpt
3) create partition primary
--There is no unallocated space at the end of the drive.

I've read that GPT stores a secondary table at the end of disk, and that the last 1 MB of the disk should not used by any partitions. I believe this explains why Disk Management is doing what it's doing, but why doesn't DISKPART follow this rule when creating the partition or even extending? I know you can specify the partition size when using DISKPART, but it seems like a bit of work to have to figure out what the size should be so that there is 1 MB left. Why doesn't it just do it automatically like Disk Management?

I know 1 MB is nothing to worry about, but I'm just more curious about why the behavior is this way. Are there some cases where you don't need the last 1 MB to be unused? Does the drive's type/usage make a difference if it's needed or not (OS/boot vs storage)?