It's simple and intuitive, pretty easy to use and pretty light on memory and CPU utilization. Includes a python scripting feature that is really fun to tinker with. I have not made a plugin yet but probably will soon.

A lot more powerful than paint but as easy to use and for my needs as powerful as photoshop but a lot easier to use.

Krita is free. You don't have to buy it, you don't have to rent it. It's a community project, and as a result you already "own" it to a degree that it is impossible with programs like Photoshop or others, no matter how much money you spend.Also has a lot of pixel art features such as pixel art brushes,palettes,wrap around mode! to create seamless textures and many more