Blend and Visual Studio - Why Two Tools?

I am here at DevTeach and having a great time. I got in a discussion with several of the speakers about the common complaint of some Silverlight/WPF folks that they want Blend to be in Visual Studio; or why Cider has always been disabled by most dev’s.

I hear the complaint a lot that developers want the functionality of Blend hosted in Visual Studio.  While I understand the desire, I’ve never been bothered by the dual programs. In fact, I think its better. Blend needs to be separate because its primarily for a Designer/UX role that isn’t comfortable with the breadth of Visual Studio.

We have plenty of other solutions that have two overlapping tools: I can insert an Excel spreadsheet in Word but when I need to do an if/then analysis I use excel.  A single Office App would be silly. Finally (I think the most compelling example) is SQL Server.  When I am in Visual Studio, I can open a database connection and run queries, create stored proces and more.  But if I want to manage users, create backup plans or other DBA-like tasks, I go to SQL Server Management Studio. I can do many of the same tasks in both, but developers never ask for Microsoft to remove SQL Server Management Studio and fold it all into Visual Studio.  Different roles mean different tools (roles != people btw).

What do you think?