This discussion is entertaining. Before answering, I'd point out that when I was certified in the mid 1980's the snorkel was mounted on the right side of the mask. The idea was that all air sources were on the right. Then apparently folks grabbed the snorkel mouthpiece by mistake instead of the second stage, which is not good, so snorkels moved to the left about 2000 or so. Then I started hearing folks said "they're a hazard" and started looking down on people who wore them, even in situations where there was no real hazard I could perceive. (I only moved my snorkel to the left when I started DM training a couple years ago. I had been diving for 30+ years with it on the right, and damned if it wasn't a really steep learning curve with the change. All my muscle memory was built in to "snorkel on the right.")
My answer is "it depends." Think about the kind of diving you're doing. For shore diving in Puget Sound, I find it helpful. There are times when there's a long surface swim to get sufficient depth to start the dive. You could carry a LOT of extra air and "plan" for doing it on the regulator, but that's a pain. Or you could swim on your back, but you miss seeing stuff underwater and your navigation isn't as good. When I'm teaching, I'll use it when anchoring the buoy. I can see bottom and when I either see 20' deep or I stop seeing bottom (in poor vis), I drop down. (I also try to keep as much air in my cylinder as possible when teaching, to make sure I can assist a student if anything goes really haywire. Call it my neuroses and planning for the worst.) I also use it when teaching when I need to see a surface skill performed underwater, e.g. remove and replace weights.
Although I don't do a lot of wreck penetrations and there's no cave diving to speak of locally, I've not been bothered by a snorkel in those situations. In wrecks I've dove and our local equivalent of caves (abandoned sewer outfalls), or even in our local bull kelp, the snorkel hasn't been what's ever triggered a hangup. That said, I "get" why it could and understand why best practice might be to keep it off in those situations. There area also rare occasions I've encountered high current underwater, where the snorkel did add some drag. However, I've encountered more occasions of chop on the surface or a planned/unplanned long surface swim where I was happy to have it.
On a boat dive in the tropics I can't see condemning somebody for either having it or not.