Many of us will agree that using tactile demonstrations is super fun and can also be an excellent way to teach a particular concept. Students engage with the material differently when they can touch, smell, or taste the objects as opposed to only seeing or listening to a demonstration. The SBI blog has had many excellent articles describing in-class tactile simulations, see here and here and here.
However, sometimes the logistical constraints setting up the demonstration take away too much from an already packed 50 minute class session. And those details get even harder with large classes. One of the biggest challenges comes from collecting data or getting results back from the students. Although some classes have sophisticated clickers that make data collection easier, setting up and using clickers is also a logistical challenge (well worth it for using all semester, but not for a one day class demonstration).
The conversation that ensues about the experimental design is incredibly valuable for understanding paired design (and the motivation for the pairing) or survival analysis (and the need for tools to analyze censored data).