This is always a great debate to start with a bunch of divers particularly with a group of divers with varied interests.
Snorkeling really is the simplest way of being able to see and breath and enjoy the oceans delights. It’s the first time you will have had to practice airway control with any kind of breathing apparatus which makes it part of the basis of water management. Most training agencies list the humble snorkel as a mandatory piece of gear at least for entry level training and have a small part of their courses dedicated to learning how to use it. After all you don’t always need scuba to explore the ocean.
Yet you can certainly argue that it goes against all principals of streamlining and in strong current they can cause your mask to leak profusely. Any instructor will know that students find them uncomfortable and in the way. Most new divers will mistake the snorkel for the low pressure inflator particularly when deflating too. So why should we have one?
The argument is for safety, for example, if you run out of air and make an emergency ascent you still have your snorkel to breathe from. This seems a valid argument yet some will counter that with an inflated BCD you will be high enough out of the water to be able to breath safely without. Unless of course there are high waves and choppy sea but then you could argue that your snorkel wouldn’t be much good in conditions like that. To my mind there is certainly value in being able to rest comfortably in the water while giving your airway the best protection possible and you the best chance of breathing easily. If you really are against wearing one then you can get a snorkel that folds into your pocket which is a compromise.