PowerCLI and Get-TagAssignment Execution Speed

I've been working on a script for a customer recently, and part of that script checks all of the VMs in their environment to ensure that they comply with the customer's VM Tagging policy.  As you might expect, this script revolves around the get-tagAssignment cmdlet and I've noticed an interesting quirk about how it runs!  I'm not clear on the "why" of it, but run these two commands and compare the results:

measure-command {get-vm | get-tagAssignment}

vs.

measure-command {get-tagAssignment -entity (get-vm)}

It's a profound difference!  In this customer's environment, piping the results of get-vm into get-tagAssignment takes over 73 seconds to run... but when I run get-vm as the entity for get-tagAssignment, it completes in a bit over 0.5 seconds!

I'm not sure what's going on here, but I do know that once I changed my script to use the -entity property it sure ran faster!

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