Some people like very simple snorkels, and I wouldn't deign to tell them what to use. Personally, I lost my last one diving off Cape Ann someplace like 15 years ago and haven't missed it. Certainly for diving a snorkel that traps air, or is bulky (so that it pulls on your mask and gets on the way if you wear it, or is hard to stow if you don't) isn't a good thing. But I don't automatically put down people who like fancier snorkels as having no technique - I know how to clear a snorkel on the way up and do, but features like splash guards and purges still make snorkeling less effort and more enjoyable. I admit I'm not a fan of truly dry snorkels, and if conditions are such that a decent splash guard and purge isn't sufficient I'm not going snorkeling anyway. But if you like to use one snorkeling, so what.
I do agree if you don't know how to clear a snorkel on the way up you should learn, it will make your snorkeling more enjoyable. (Though I'm not sure you can do this with a truly dry snorkel.)
I have a rigid semi-dry snorkel for snorkeling, which I don't dive with as I have no good place to put it. I carry a roll up snorkel when diving, which I wouldn't really want to use for extended snorkeling, even though it does have a splash guard and purge. I see them as 2 entirely different tasks.