- Your face and hands don't get wet, even when the rain is blowing sideways. (Coat-only waterproofing also leaves you with wet jeans and shoes.)
- You don't get basically just as wet anyhow on account of sweat being trapped inside the clothes. (Even "breathable" stuff traps sweat when its outside is slick with water.)
There must be a better solution to umbrellas getting inverted. Why do they even have to bend that way?
I'd be very hesitant to claim that I could design a better umbrella. They've been evolving for a very long time. Maybe modern materials would help, but I for one wouldn't dare buy a carbon-fiber umbrella because I just know I'd leave it on a bus or something. Cheapness is a feature too.
Meanwhile, the hilarious invention at the link not only looks ridiculous, but I'd have to be convinced that it wouldn't drip all over my lower body. And how on earth do you carry it when it's folded up? A big feature of the standard umbrella design is that it's not that hard to carry or store while folded.
I have a nice waterproof hat from Outdoor Research and a Gore-Tex jacket. For serious swimming I've also got waterproof pants and even gaiters. That combination seems like it would be superior to the space helmet.
As great as the Senz is, it lacks one of a regular umbrella's most compelling features; its handle is inconvenient to use, and, combined with the lack of a pointy end, you can't use it as a walking stick of sorts. This also makes umbrellas feel less cumbersome, because they still serve a purpose, when it is not raining.
(And it also makes it more difficult to hum Singing in the Rain to yourself and pretend you're Gene Kelly.)
That's from the top of my head.