Yes spirulina is 100 percent vegan so if you're a vegan then eating spirulina is good for you and will keep you as a vegan.
The spirulina also has a lot of health benefits other than just being vegan and it contains a lot of protein and essential amino acids.
You can eat spirulina for the health benefits or even take some spirulina supplements which will also provide you with near the same health benefits of spirulina.
I take a spirulina supplement every few days to get the health benefits because I can't stand the taste of eating spirulina directly.
However some people have learned to love the taste of spirulina but for me I could never get used to it.
The spirulina and spirulina supplements are high in Vitamins and other nutrients as well and are anti inflammatory, antioxidants, lower blood pressure, prevent cancer, lower cholesterol, protect against anemia and can also lower your Triglyceride Levels.