Why one should not edit a VM disk when the VM has got snapshots?

Hi Buddy's,

         I have one VM named "abc" with base disk abc.vhd and one snapshot "abc_snap" .  So after taking the snapshot my VM "abc" started pointing out to the new disk "abc_snap.vhd" . But when I try to edit this new disk in the Hyper-V VM settings wiard , I can get to see some warning message like "Edit is not available because checkpoints exist for this virtualmachine" and "Edit" button will be in disabled mode.  My first question here is "Why should not I edit a disk when the VM has got snapshots" . In my case "abc_snap.vhd"

  But Actually there is a powershell comandlet "ReSize-VHD" allows me to edit the disk even when the VM has got snapshots with it. Its usgae is "ReSize-VHD -Size 10 GB -Path abc_snap.vhd" (I am trying to resize it from 5GB to 10 GB in my case).

  And with this commandlet I expanded my vhd to new size and powered on that VM and everything so far so good no issues I faced.

  So my second question is "why is this in-difference between UI functionality and the commandlet functionality?"

        guys please help me out here to understand the concept correctly

Thanks in advance.

Your's Rakesh