People don't care about defence, that's why they go for wolver and gunslinger gear, right? Why these two pieces? They do the same as Fencing Jacket and Cyclops Cap, the only difference being defence offered. Doesn't that seem like a waste of CE?
Why do people make Skolver Coat and Shadowsun Stetson?
People do care about defense, except for a small minority of elites (and wanna-be-elites). By the time one reaches this elite status, one already has 5-star gear. But it's good of you to point this out. I imagine that we'll see a few people exploiting this insight.
The health difference is quite huge also.
I raised an alt to Vanguard with Pepperbox, Swiftstrike, Cyclops Cap and Demo Suit (working on replacing it with Chaos). Passed Hall of Heroes with Ancient stuff.
It's pretty viable, but Pepperbox has a couple of defensive flaws. Get a fencing jacket, pair it up with a toothpick, no problems anymore.
There's a vast amount of difference between not caring much about defence and docking yourself a ton of normal defence, shadow/piercing defence, bonus health pips, and Max! Poison/Freeze. Most people do not start out as pro enough to be able to do this throughout the whole game.
While I'll admit they are much better choices than most people will give credit for, it's simply that the vast majority of players will not start a new character with the skills to avoid all damage. People will want some leeway, as opposed to 'make one mistake or have a second or so of lag and find your dead and broken corpse on the ground'. (Chaos gives enough health to be reasonably able to survive if you take a hit or two in a row without healing.) And while I'm aware you can use Sonic Mode, there's also the matter of statuses... particularly shock and fire.
But neither of those pieces protect against shock or fire. All those resources could go into other equipment, like Vog Cub, Divine, or Gray Feather, increasing the player's options. By all means, go for Skolver Cap and Shadowsun Slicker, but their counterparts just seem like bad options.
5 health pips won't last terribly long if you're on fire or being shocked.
Because both these sets are mostly used in LD, and if you go with a cyclops cap and shadowsun slicker, You'll get killed by a flourish in two hits.