Why not just use Remington 125 grain medium velocity Golden Sabers (1220 fps/4 inch)? Or something like Winchester 110’s (1295 fps/4 inch)?
As I mention in the rest of the post you quoted, it isn't totally unlikely. A 9mm revolver will be steel framed, and 9mm snubs do have a reputation for some kick. So, by going with lighter (110gr and 125gr) and/or low recoil snub loads the recoil in a .357mag likely wouldn't be much greater than in 9mm, and the steel magnum (to tame the recoil) wouldn't be any heavier on the belt than the steel 9mm snub. There is also a little bit of tradition going on, revolver guys tend to be traditionalists, and .357mag is a traditional revolver caliber and 9mm is not. Finally, psychologically, it seems odd to in some ways to go 9mm in a revolver, it is an auto caliber and I can get a 9mm semiauto in roughly the size and weight of a 9mm snub that can carry 15 rounds of 9mm (especially if I go 3" for the snub) and easily 10-12 rounds instead of the 5 rounds of 9mm of the snub.
As for cheaper practice, 9mm in a snub recoils close enough to .357mag (especially the 110 and 125gr variations of .357) that I probably wouldn't shoot more than a box at a time anyway. I could also add a .22lr snub and get a lot of very cheap practice when I didn't feel like reloading .38 and .357 (while I do reload revolver calibers, I don't particularly enjoy reloading so I don't do it often), and a few boxes of .22lr wouldn't take much room in my range bag (countering the advantage of a one caliber range trip).
There are several positives for the 9mm as well. Cheaper and easier to find ammo (recently there has been a lot more 9mm available than .38 or .357mag). Variety is nice, and buying (and sometimes carrying) a 9mm snub doesn't mean my .38s will be retired, I'll never load another magnum in my .357s or that I won't also buy a 2" .357mag snub. I like 9mm, I've recently added a 9mm 1911 (even though 1911s should be .45ACP, .38 Super or 10mm IMO), I simply want a 9mm version of each style of gun I like to shoot. Having a bit more oomph (in both the recoil and power departments) vs. a .38 but less recoil than the magnums may make it the happy medium. Historically, 9mm JHPs have been able to more reliably expand than .38spl, and sometimes better than .357mag out of a short barrel. Over the last decade or so with the advances in 9mm hollow point development that hasn't seen the same effort in the revolver calibers, 9mm may actually be the better choice these days (especially with the lighter recoil) vs. even a .357mag out of a snub.
Now that I've decided I like snubs and no longer just have them for the utility of one or two, I'll likely add a few and not just one (I am a bit of a collector type in almost anything). I will eventually have a 2" .357mag snub again (or several), a 9mm (2 if I get both a 2" and 3"), and a .22lr (plus a .22magnum). In some ways that does make it harder to decide. I see the advantages in all of them (.22, 9mm, magnums), but I'm not likely to buy 2 or 3 at a time. So, which do I get first? Maybe a 9mm since I've never had one and I do have a 3" .357mag snub, but not having a 2" .357mag snub, if you are a snub guy, is a pretty big hole in the collection.*
*Note: I do have both a 2" and 3" Rossi 461 (6 shot, .357mag snubs), but I don't trust them (especially the 2") since the 2" has had cylinder binding issues when shooting magnum rounds a few times in the past. It has likely been 5 or 6 years since I've shot them, and I definitely wouldn't ever trust them as carry or home defense guns. So, I don't really count them (and I will be putting them on consignment as soon as I get around to going to the gun shop with the lowest consignment commission in the area, but it is about an hour away with limited hours so it is tough finding the time).
even. He told me the amount and type of powder he used -- uh oh 
. They leaded the barrel of a snub I had in less than 50 rounds. 
