My guess is that DMT would vaporize very fast. If the hot plate was hot enough (in the video it seemed plenty hot) I think it would vaporize almost instantaneously, with most of the vapor billowing up and out before it can be inhaled. (Unless you’re already inhaling before adding the DMT?)

This would be easy enough to test – just get a suitable piece of metal, heat it up, dump some DMT onto it, and see what happens!