It’s not just for snow. In general, moisture management is a huge deal in construction, and having a surface that naturally causes water to go away rather than collect is a boon. You CAN do flat roofs but they are more expensive and complex and require more maintenance, so you for residental applications the trade off against useble roof space doesn’t make sense.

Why would you want 14 ft ceilings? That sounds awful.

With gable roofs you can put mechanical systems / ducts up there and use it for storage, especially if the attic is within the envelope of the home.

I have 14 ft ceilings in most of my house. It’s great other than the heating and cooling bill.

Austin has snow. There was actually quite a lot as recently as February 2021 when Austin got 8 inches of snow in a few days.