Seriously, there are a lot of posters really invested in getting OTHERS to adopt the equipment/ configuration that is appropriate for the POSTERS' diving. There are lots of examples in both directions in this thread (and throughout diving in general it seems).
Have to call out a pretty egregious example, but believe me (and most any California diver), yes, there are GREAT MANY shore dives that greatly benefit from long surface swims. Maybe Im just an air hog, but if the site is 250+ yards (or even just 50 yards) from shore, Id rather use my air on the site, as opposed to traveling to the site.
Additionally, it would take at least twice as long to scuba as opposed to surface swim. I love to scuba, but mostly featureless sand bottoms lose their lustre after awhile. Also, air is cheap, but it isn't free. Im gonna save it for the pretty stuff underwater.
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To answer the OP's question.
Locally, I mostly shore dive. I swim on my back, and don't like the snorkel on my mask.. However, I dive with folks who snorkel on the surface, with a permanently attached snorkel. I would HATE that, but it works for them.
I have a pocket snorkel. For my local shore dives, I probably have about a 0.00001% chance of ever needing it, but since I have it for boat dives (where I have maybe a 0.5% chance of ever needing it), may as well bring it along permanently - as someone else stated, it basically lives in my pocket.
I would not question why a cave diver -- or even someone who just hates snorkels and is willing to discount the ~0.5% chance of ever needing it, or has no room in a pocket -- doesn't own a snorkel. I realize folks have different manners of diving.