In addition to what others have said, that's an accessibility concern. There are many people who have a physical inability to handwrite.

https://en.wikipedia.org/wiki/Dysgraphia

In some ways I'm grateful for Covid's impact on the job market because I now have many alternatives to physically drawing on a whiteboard. I can use TikZ as fast as my professors can draw, and I can put that on a monitor in a conference room. I've even used it on exams before.

I would probably struggle for reasons unrelated to my actual competence as a programmer if I was forced to use a physical whiteboard during an interview. Your comment made me appreciate that I'm graduating into a different world than 4 years ago.