It is now.
Before when fireworks was made by Macromedia, it was the ideal tool to make web graphics, signatures, static web banners etc. It handled transparency, compression for web, animated gifs etc very well. There are tonnes of styles that you can apply to any graphics, quick vector drawing work etc.
Photoshop back then was all about print, only in the last CS versions did it catch up on the web side of things. I guess the takeover of Macromedia by Adobe had helped in this regard.
I still prefer to use fireworks to come up with quick graphics. For larger, more thought out graphics/vector drawing, Illustrator takes over. With Photoshop I still feel the need to start off with a photo!