Elementary Schools use those as aids to teach kids about coins and simple Math problems and making change and such ( they are probably afraid the kids will steal real coinage ) . I guess that's not keeping the kids from snatching them up though as we are still finding them .
I've found a plastic coin or two from the CS before... I've not found anything in CS's since Covid hit - 1) I stopped commuting and checking and 2) the local ones have been barren or just a tiny bit of clad.