From what i've gathered during my research into this.
It provides free crypto blockchains with smart contracts like Ethereum to anyone that wants it. So any organization, businesses both small and big, and private individuals can get their own 'Ethereum''. All these instant free sidechains will be connected to ARK, which will do fiat/euro processing etc, and also connects all these millions of sidechains with the rest of the cryptocurrencies by smartbridging.
tl;dr with ark you can pay for any service or application in the cryptomarket offered by any and all legitimate crypto currencies, and you can also have instant ethereum for yourself.
I think 99,9% of the market still has no idea what the impact of such a currency will be, and they are almost launching these features (1,5 month +-)