Yeah, i also started considering introducing cassettes for several of the reasons you state above, especially the ease in which you can make the cassettes. I have been a little hesitant because it feels like buying empty cassettes is pretty hard when it comes to the cost, it is pretty cheap to buy a lot of empty CD:s (In Sweden you can get 10 for less than a dollar each) but cassettes are several times more expensive and there is a much bigger lack of options for cassettes in second hand-stores.
But you have a great point regarding the durability (and the sound and esthetics). I have been a bit afraid of them playing with the tape and me having to detangle it, but maybe that is not such a big problem. Especially when it comes to compact players, i bought a cheap second hand portable cd-player for my 4 year old to listen to with headphones, but they seem very easily breakable compared to an old tape deck. But now i'm feeling pretty inspired so I think I might try getting hold of an old portable tape deck and try!