Innogy post mentions Fiat tokens on iota. Could this mean that iotatokens will soon be worthless?

No. You must mean the graph in Stoker's blog - https://medium.com/iotatangle/automating-machine-transactions-and-building-trust-in-the-4th-industrial-revolution-d3219a157396#.852c69mik

To me it looks like through an outside wallet, the other crypto and fiat tokens can interact/inter-operate with IOTA network(for instance, IOTA can inter-operate with Rootstock and Ethereum as an oracle and data provider). To achieve the high efficency, within the IOTA network and the machines, IOTA token is the medium for exchange and trade

I should have looked closer. It looks like you've said. I somehow thought you could have all kinds of tokens on the iota network tho.

colored coins will be possible with iota, as well.

and in the meanwhile we can just use eth smart contracts.