Would you happen to know how much zeny he charges?
Although even if it's possible to buy without KP, I can't imagine it being more convenient then Ragial. I check Ragial when I can't see my vends in game (when I'm in class etc), which is something I obviously won't be able to do if my only searching option is a poorly-designed in-game item,
And does the catalogue even list buying shops, for that matter?
Uff... I dont remeber very well, i think something like 200 z... But not 100% sure.
And, the window shows the shop name, but not the location like ragial...
And, if i recall correctly, the catalog from the kafra shop lets you shop directly from it.
Also, it let you search for selling and buying items, but it is case sensitive, and if you write the item name incorrectly, it takes one search away...
At least, that is the behavior on a private server that was in sync with kRO, but never tried in iRO.