If you build a store that accepts them they have more purpose than Bitcoin. A token with stable value is far easier to use as a medium of exchange than Bitcoins whose price fluctuates wildly and is non inflationary.
The small market value of tokens also make them easier to tailor fit into a micro ecosystem.
Has anyone coded transactions like this with erc20 tokens?
I don't think decentralized token with stable value exist. And usually they're manipulated very easily due to low trading volume and low market cap.