Yep. At least with 124/125 grain bullets and loaded to their full potential, the 38 super and 357 sig are ballistically very similar.. basically 9mm +150fps. The difference is literally where the .357 sig and the 38 super store the extra powder to produce that additional speed. The 38 super is longer, and it stores the powder in a longer column. The 357 is fatter, with a necked-down 40 base, and it stores the powder in a fatter cylinder of similar length to 9mm.
- If you care about ease of reloading, total magazine capacity, and/or grip width, the 38 super is the cartridge for you.
- If you care about grip length (fore and aft) and/or need a cartridge to run in a gun that only has the slide-movement window to accommodate 9mm/.40S&W length ammo, then 357 Sig is the one for you.
In the practical pistol games, magazine capacity is a huge deal, and ease of reloading is also very important (competitive shooters are high-volume shooters, and most reload their own ammo in significant volumes). Most people in the relevant equipment division are shooting 2011-based things with plenty of stroke length and grip length for a .38 super, so there's literally no advantage to the 357Sig for them. The .357 Sig sees absolutely no competitive use outside of people shooting their first matches with non-gamer gear or someone purposely using their duty gun or the like.
The real question in the relevant division is whether to shoot 38 super or 9 Grenade (9 Major), which forces 38 super/357sig performance out of a 9mm case.