This would fall into the category of the George Mallory quote ... “Because it's there". If you don't know the story behind it, Google it.
My preferred round is the 357sig, but I'm not looking to debate the 'best' round.
I have a SilencerCo Hybrid and love the suppressor. It is insane how quite it is. There is almost zero recoil with a Speer 9mm 147gr round.
When I received my Sig 9mm compact threaded barrel I noticed its pretty much the same size as a full size 9mm barrel. This got me to thinking .... if compact 9mm threaded barrel is just a full size barrel with threading, why couldn't someone thread other full size barrels for use in a compact slide.
I didn't bother asking Sig customer service around this because they will go by the book and say its not supported.
I ordered a full size 357sig barrel from Sig. It came in about a week and a half.
The FS 357sig barrel is, visually, the same as my 9mm threaded barrel. I has already measured my various 9mm, 357sig and 40sw barrels. In those measurements, I found the only difference was the 9mm barrel was .5mm smaller in diameter. Also the 'tab' above the breech face is a hair narrower.
I contacted the dealer here in Denver I used to purchase the Hybrid and ran the plan past him. He partners with a local machinist specializing in gun parts. All of his threading is done via CNC. The threading package also includes a thread protector.
He confirmed the Hybrid could easily handle the pressure of a 357sig (which I already knew).
I dropped off the 357sig barrel, Sig 9mm threaded barrel and my 13x1LH piston. The 9mm barrel and piston are for reference and fitment.
The barrel should be done in a week or two.