Photoshop allows me to do so many things -- photo editing, digital illustration and painting, 2D game design, cleaning up scanned documents, and meme generation.
Although creative cloud makes it a lot more accessible price-wise, it's not cheap software. However, it does pretty much everything.
Also, the text tool could be a bit easier to use.
Photoshop is an expensive tool, but it's unparalleled in terms of features and ease of use. If I could have only one tool in my entire workflow, this would be it.
We use photoshop to edit images for our website and web app. It allows us to quickly mock things up, change colors, edit, resize, and merge images.
I also have Photoshop CC at home for personal use for game development and digital illustration work. It allows us to quickly make 2D game art assets in any style, including 8-bit, and export them for use in our game engine.
You could build an entire company out using this one product alone by creating and selling designs or illustrations. Lots of illustrators and web comic creators either draw directly in Photoshop, or create art using a traditional media and then scan it into Photoshop to do color correction, contrast changes, cleanup, and resizing for print.
I also use Photoshop personally for photography, and the same applies: import RAW files into Photoshop and you gain access to a ton of amazing features and tools to achieve pretty much any look you want.