Given the premise:
For me, it takes a lot less time to write linq to sql code than it does to write a bunch of stored procedures. That's especially true when the design isn't finished, in that case I don't yet know how much of the work I want to do on C# objects, and how much I want to do in SQL.
So, I can skip building datasets, I don't have to click click click to add queries, basically, linq to sql means I can change my code in less time.
Also, as a big fan of Haskell, I can write lots of functional-style code with linq to sql and it just works.