Is your question: If you already own licenses for Informatica, Datastage, etc. as tools at your disposal, why would you purchase DI?
Or is your question: Why might you choose DI over those competing tools?
You can search these subforums, as others have asked the same question.
If you have no other BO products, I think it’s a tough sell for DI. But if you have other BO products, it should be high on your list. DI is generally just as good as those other tools, and the pricing is competitive.
However, if you’re a SQL Server shop (solely), and you have SSIS as an option, then it’s a tougher argument to make IMO. SSIS isn’t still at the level of sophistication that DI is, but for many small-to-midsize companies, it is “good enough”, and the price is hard to beat.