I think this is a wonderful dataset for teaching and will certainly try to include it in the assignments I write.

Other datasets I tried:

Fashion MNIST has so many mislabels and also is pretty trivial to separate with UMAP alone

Google's QuickDraw is better than MNIST, but I also haven't tested it against e.g. log. regression.

Of course there is CIFAR but those images hardly look like images. I can't classify half of them.