I've been diving for fifty five years and have carried a snorkel on every one of those dives. In my NAUI class, there was training for it's proper use. Most of the time, it was on my mask but sometimes if there were overhead obstructions, I stuck it in my knife straps. Honestly, I don't think I've ever dove with a partner who didn't have one with them! In fifty five years of diving, I have had to use it at least once for an emergency. It is doubtful that either one of us would have survived without our snorkels.
I have seen divers getting ready for their dives and checking their gear over and over again making sure all was right. I've watched spare masks and fin straps and and extra computers and mini air bottles and fifteen whistles and extra line cutters and cord and an extra glove, etc. etc. all getting stuffed into assorted pockets on themselves. What? No toilet paper? Sheesh! I always asked myself why do they carry all that junk and no snorkel? If you can't find place for a little plastic tube, you're not trying hard enough!
Do whatever you want. I'm enjoying the conversation but I really don't care if you have one of not. I guess it's a personal thing, like whether to carry a spare tire in your car. You'll probably never have a flat. Probably. You'll probably never have to bet your life on a snorkel. However, if you do, you'd better have your own because you're not getting mine!