Get more information without switching between forms: functions, names, graph view, hex-view
IDA and HexRays side by side
The default debugger layout.
Easily navigate between different windows. Very useful for keyboard lovers.
The debugger window can become floating, so you can move it to another monitor if you wish.
Dynamic decompilation with the debugger and HexRays side by side
If the old MDI interface is still preferred, it is always possible to float all windows.