Actually, all this video shows is that one filter is (possibly) cooler than the other, but it doesn't compare it to no filter at all (unless he does a video about that as well).
I found this really interesting. Yea he would need a control, he's thinking the first temp is the control, but a unfiltered would be the real control.
Looks like he does a few no filters, same pipe, same blend, but strangely found both temperatures to be hotter with the difference being greater as well. He also tested churchwardens.
He concluded that the filters definitely made the smoke cooler, but he would need to control for airflow volume before he could say it was specifically due to the filter and not the restricted airflow the filter causes.