Are Burpees considered a strength workout? And are they perfect for wieght loss?
Strength is developed by progressively training against resistance. Burpees are not much of a strength exercise. They are a high level conditioning exercise, low to mid level power exercise and are very poor at strength development, compared with actual strength exercises like the barbell squat, deadlift or bench press. You want strength with calisthenics? Progressively weighted pushups, dips, (towel) pullups, ab wheel rollouts, squats, lunges, pistols, shrimp squats and both wrestler's and gymnastics bridge should be in your program, as well as isomatric/self resistance exercises for your neck.
That being said, if you are fairly weak, you will build up to a certain level of strength with burpees when you first start doing them, but once you can do, say, ten or more of them in a row without stopping, you will have developed about as much strength as they can give you (unless you add a weight vest, for example, but even this is limited), and would be only increasing conditioning and muscular endurance from that point on. But if you are weak enough that burpees would make you stronger, you really have no business doing them yet. Do the other stuff I mention first to build the strength base that will support doing burpees without getting injured (yes burpees can injure weak shoulders).