Pixel art is all about putting meaning behind each pixel since it's such a small scale. I believe size of canvas is irrelevant in determining whether something is pixel art or not so I'd pay more attention to the intent and whether there's an actual reason for certain pixels to be arranged in the way they are.

For example, Songs of Conquest by Yes I Do is 1024x514 but is clearly pixel art.

Also I don't think color count should be a big part of deciding. You can have a lot of colors but how they're used is more important. Additionally, high color count usually occurs with beginning pixel artists and they'll eventually learn to how to use less and be more effective with less.

As others have mentioned, Pixel dailies help get people started and also helps their name get out there to interact with the community. However the main thing I get out of Pixel Dailies is art which sounds obvious but when I'm in an art block (which is a lot of the time), being provided with a prompt sometimes gets hidden creative juices active. Additionally, I find it fun to browse what others have made and see how they interpret things.