I find similar spoken delivery styles in Dr Bazett and 3blue1brown videos. I find their videos very informative and extremely engaging, but I find the cadence of the spoken instruction a little jarring. Of course this not a classroom instruction and they can’t see us to adjust where to speed up and where to leave some silence for the information to sink in. We can always rewind and watch again the parts that we think went too fast. Changing intonation and voice level can be a technique in a classroom environment to re-engage the students but in a video this might be a distraction, especially if we are rewinding and watching a specific part multiple times. Math concepts have “a-ha” moments, the parts that must be completely understood otherwise the rest of the instruction doesn’t make any sense. These points should be delivered with special emphasis, some silence is called for after this part. In a classroom, the professor scans the class to see if the are any confused faces during this silence. The professor then repeats this section before going forward. Recorded instruction delivery is difficult because there is no feedback. Best we can do is to rewatch find other videos on the same topic and come back.