I am sure this has been posted a thousand times by now, but I can't seem to find any solid threads or articles.

All over the internet, I see people speaking about how great Photoshop is for web design, and I simply don't know why.

I have always used InDesign. It has a built-in grid system, paragraph/character styles, master pages... the list goes on. Sure, I may not use InDesign for exporting elements, but for wireframing and mock-ups, definitely.

Am I missing something here? Why is Photoshop so great for web design?