This is basically following a rising demand (AKA stubbornly resident fad) over here, and I´m ready to admit it has its value, since these combine advantages of both valve systems.
You will be aware of the "Gansch Horn" in both trumpet and flugelhorn versions, as played masterfully by Thomas Gansch of Mnozil Brass.
This is basically a variant of taking things down an octave into the Basstrompete / Bassflügelhorn world.
Small and excellent groups of seven to maybe ten musicians putting on their Lederhosn, playing alpine music to all rampant beerfest-type crowds, has been on the rise as business opportunity for the best part of two decades, now. Search for "Woodstock der Blasmusik" and you know what I mean.
You, Bloke, already know the record I´m about to put on for the remainder of this post, but for others: Here goes...
Many of these groups adhere to perceived stereotypes in appearance as well as choice of gear.
Trombonists will double on tenor horns or baritons in oval and horizontal versions as shown in your picture.
If they want to appear conservative / classy, they´ll choose the oval variant as well as tidy shirts and vests with their Lederhosn.
https://www.kaisermusikanten.at/
If they want to appear less streamlined and pretend to be more individualistic, their uniforms and standard equipment comprise bare feet optionally in rugged shoes, Lederhosn boasting decades of wear, T-shirts with artificially worn-off collars and printed-on "sweat stains", a Bergkristall on leather necklace and brass instruments stripped of lacquer / showing discoloration from torchwork and may use horizontal tenor instruments.
These
https://www.labrassbanda.com/ are just among the most successful groups.
The shown specimen would be situated somewhere in-between.
(A friend of mine owns one of those fancy European boutique bass trumpets. I pulled out my flugabone and showed it to him. He played it. Guess what he went and bought?)
