The pressure which they put on the shoulder joint, if you are going to do lateral raises make sure your elbows are flexed otherwise you're asking for shoulder impingement, they're also isolated exercises. Pec flies are also isolated, while your biceps are involved in an isometric contraction, they're not getting hit properly. Not to mention these are not functional. In the shoulder joint stability is compromised for mobility, by strengthening the muscles around the shoulder you improve stability, but when you don't balance out your workouts you end up with imbalances. Your scapula (shoulder blades) relies on muscles only to keep it on your ribs, when you neglect these muscles by not hitting your back muscles enough you end up with problems like a winged scapula.
When you choose an exercise especially if you're short on time you have to consider if there's a better more compound movement. Think about how functional the movements are too. Exercise is supposed to make you better at moving, not worse co by compromising the integrity of the joint.