Here's a more in-depth explanation.
Property numbers:
Barbed Kit: Can make items with only 4 properties.
Valorite Hammer: Always makes items with 5 properties
Property Intensities:
Barbed Kit: Minimum intensity is 50%
Valorite Hammer: Minimum intensity is 85%
As you can see, just from that, Valorite hammer-made items outclass Barbed kit items, except for two minor factors - Mage Armor/Meditation and STR requirements.
That's where the Samurai Empire Plate Armor types come in.
The Japanese-style plate armors from SE get Mage Armor as a free property, when made exceptional (which typically requires using a VERY good blacksmith Exceptional talisman and an Ancient Smith Hammer +15 or +30, in conjunction with the Runic). This ELIMINATES the major advantage of leather.
Furthermore, Valorite Ingots, used to craft armor, are superior in total resists to Barbed Leather. Verite ingots have the same total number of resists as Barbed, but spread more evenly. So, this armor is also attractive to those people whose STR is high enough to not be knocked out of their armor by a Curse/Weaken (most PvP melee builds).
Total resists (Ph/F/C/Po/E) & properties
Barbed Leather 2/1/2/3/4 = 12
Verite Ingots 3/3/2/3/1 = 12
Valorite Ingots 4/0/3/3/3 = 13, plus 50% Durability Increase
Comparison: Barbed EX Leather with Barbed Runic vs Valorite Ex SE Plate, with Valorite Hammer (100 Arms Lore, excluding SP & Mugen)
Minimum Resists (materials):
Barbed: 4/5/5/6/7 + 11 random. Total: 38 resists
Valorite: 9/3/5/6/5 + 11 random. Total: 39 resists
Resist properties (from Runics):
Barbed - Minimum of 8* per resist property rolled. Average 11.5
Valorite - Minimum of 13* per resist property rolled. Average 14
*might be 7 & 12; but if so, the difference between averages would STILL remain at 2.5 per property in favor of the Valorite Hammer.
ALSO, a 50% chance of a barbed runic item having ONE LESS PROPERTY than the Valorite Hammer item.
Addendum
For those building a purely PvM suit, centered on Luck, Gold ingots give 1 more resist than Spined, with a much better distribution, and with a minimum intensity for a crafted Luck property 35 higher than a Barbed kit's minimum, using the Valorite Hammer. Of course, half the suit will still probably be Artifacts, but that 200 luck ToT3 Mempo (gold-colored leather) would look perfectly in-place with the other SE parts of the suit.
Total resists (Ph/F/C/Po/E) & properties
Spined Leather 5/0/0/0/0 = 5, Plus 40 Luck
Gold Ingots 1/1/2/0/2 = 6, Plus 40 Luck AND 30% Lower Requirements! (making the suit much easier to wear)