I think it's intended purpose is supposed to be making token creation on their chain very easy. I suppose that puts them in direct competition with Ethereum and some of the Eth token ICOs.
However, there's projects like Zrcoin that are both tokens on ETH and on WAVES. So I think the business case is that if you want to create tokens very quickly - use Waves. If you want to do more complex things with the tokens (like using Solidity) - you could later somehow bridge your tokens between both Waves and Ethereum. I think the biggest unseen use case from that might be the commodities market, maybe even product inventories for companies at some stage.