Megapixel only tells size but the more megapixels a camera has, the better the picture looks when you zoom in. It's just that we don't usually look at pictures zoomed in all the time. Overall, picture quality isn't determined by megapixel count. It depends mostly on the skill of the photographer. The camera is only a tool. What tool the photographer uses tells a lot about his skill.
Then there is the matter of pixel size. The more megapixels, the smaller the pixel. With phones having tiny sensors, more megapixels contribute more to the degradation of picture quality. That is why phone manufacturers limit the number of megapixels to around 12. To benefit from more megapixels, use a camera with a bigger sensor.
Anyday of the week, I'd shoot with my nostalgic 6MP dSLR rather than any of the latest high MP phones out there.