They are not worthless. It all depends on the need of the person. They have been on sale as low as 300 I think.10 generation iPad and lesser generations are worthless now. Your better off with iPad Air with a m2 chip if anything at all.
Personally if one is looking at the 10th get iPad, I would suggest they look at the M1 Air, Walmart has or had it (depending if its on stock) for 399, you get an M chip, 8gb of ram, its laminate, you can use the apple pencil with wireless charging etc.