ClaimsPrincipal action injection

Personal preferences aside, are there any technical reasons why you can't or shouldn't use a technique similar to the one detailed in https://www.hanselman.com/blog/IPrincipalUserModelBinderInASPNETMVCForEasierTesting.aspx for .net core (e.g. security, missing functionality, etc.)?

If relevant after the first answer, are there preferred alternatives? How would they work if you wanted a custom/extended ClaimsPrincipal?

Thanks in advance!