What is the point of checkpoint?

I get the idea of them but I keep reading that they are not to be used to replace back ups which I understand but was setting up a new virtual domain controller yesterday and I came across this MS article and it says:

• Do not take or use a Snapshot of a virtual domain controller. It is technically supported with Windows Server 2012 and newer, it is not a replacement for a good backup strategy. There are few reasons for taking DC snapshots or restoring the snapshots

https://docs.microsoft.com/en-us/windows-server/identity/ad-ds/get-started/virtual-dc/virtualized-domain-controllers-hyper-v

I thought a snapshot or checkpoint would be good to use before applying updates and rebooting the domain controller but after reading that they seem a bit useless on a DC