I follow a vegan diet for mostly health reasons. I find it easier to achieve/maintain a healthy weight when I don't eat any animal products. My husband doesn't mind that he's mostly vegan these days, since there are lots of tasty recipes at my disposal. For protein, we eat a variety of beans, nuts, and whole grains.
I'd say it's difficult to be a lazy vegan and be healthy. In the past when I've gone vegan, I haven't spent as much time preparing meals, and therefore just ate whatever was quick (and not necessarily nutritious.) I had no energy and started eating meat, dairy, etc again.
However, if you have the time, patience, and ambition, a vegan diet can be very healthful.