Yes this is the official truth. Personally I feel it is more about aesthetics and of making a heavy shoe like a long wing / country brogue look more robust than about the usefulness of preventing water from ruining ones day. Unless someone enjoys jumping in ponds with their expensive shoes just for shits and giggles.
With all due respect, but this is pretty ignorant. Storm welt definitely makes a shoe more waterproof. The major place where a traditional shoe leaks in water is from the side between the welt and the upper. Much more than through the bottom of the shoe, through the sole stitch. The storm welts secure just this area in a much better way. You don't have to walk through ponds to experience the difference here.
Remember that the main problem with water going into the shoe is not that your feet get wet, but that the inner parts of the shoe gets soaked and therefore wears out a lot faster. This is not up to personal opinions, I'm sorry. If you find it ugly, that's fine, of course. Actually I'm not a big fan of the look either. But I wouldn't give advice to people that storm welt is a scam, when this is false.