People choose straws for many reasons, we're sure
Straws are a simple instrument that serves a simple purpose: A thin hollow tube (usually plastic) used for transferring liquid from a container to the mouth. Some studies have shown that straw use to be beneficial with preventing teeth staining and erosion; while also decreasing bacteria and germ exposure when consuming beverages from cups and glasses at restaurants and other public areas.
Straws also come in handy by decreasing those unpleasant situations where you raise an ice-filled cup of something to your mouth, only to have that ice shift so both that ice and the something else hits you in the face.
But ordinary rigid straws are flawed and generally only work with smaller sized cups. Beyond 20 oz. or so, the base of the straw fails to sit at the bottom of the cup, so you end up having to drink with the rim to your mouth. Which is fine, we guess, but that defeats the entire purpose of choosing a straw to begin with.