Many coins are exactly the same as real coins. Sample coins are only used as sample coins, but in order to distinguish them from real coins, the words specimen are often printed or engraved on them to prevent sample coins from participating in circulation and disrupting market order.
English sample means sample. China's sample coins are generally printed with China's sample coins.
Sometimes SPECIMEN is abbreviated as SP.
SPA should be written in Latin in other non-English languages. I have seen sample coins marked SPA in non-English speaking countries.
As for why the landlord used SPA instead of English specimens, I estimate that this is the US dollar sample that non-English speaking countries have been using.