With a lot of AC background autoranging can be a little tricky: the choice of range must take care of the peak values, not to saturate. So the average DC reading alone is not good enough to decide which range is best. A cheap meter may not have extra means to also measure the peak values. One can be lucky and peak causing clipping are at least detected, so autoranging with some try and error, but than no good / reliable way to detect if it is possible to switch to a lower range.Open probes is not a very relevant case. Still it would be a bit anoying if the meter would frequently switch relais in this case - I faintly remember such a case with a constantly clicking meter (AFAIR this was a HP3478).
Not being able to fine adjust the integration time in detail is not such a big deal for a meter in normal use. For 1 PLC and more there is no big difference between a longer integration at a piece and averaging over multiple readings / digital filtering. Especially with a SD ADC this is essentially the same. DMMs with a multislope ADC usually do more than 10 PLC via averaging.
For just the number display and no graph there is little need for less than 1 PLC. It can still be useful for data send to an USB stick
If the main part of the lesson is to learn about the DMM function / intenals, it would be nice to really adjust the details, In this case one would however like even more detailed information and settings, e.g. also about the auto zero mode. I don't think this meter would be right canditate this special task.
For normal use simple handling (no real need to read all the manual) would be way more important. There are usually more important parts to learn with hands on experiments. The meter should just work as a simple to use reliable tool.