I think this is not such a bad thing at all. If I see an item I like from a CI, but it's stupidly rare and I happen to have the GC to spend, I'd rather spend it on the item directly from the MP than try my godawful luck at the CI. Honestly, I think it could lead to deflation rather than inflation, but it'll take time. Like all new features, they're still testing this one, so I'm interested to see how well it works.
Edit: I'd also like to note that lots of MMORPGs (example: Guild Wars 2) have a gold to gems (cash) conversion in-game. Now, you can't buy user-listed items for gems, but you can convert your gems into gold to buy the items if you reeeeally want to. Or, if you make a lot of gold and want something from the gem store, you can convert your gold back to gems. If Gaia makes a habit of releasing the Kicopots in conjunction with the new MP feature, it might work out rather nicely. The Kicopots are a risk, of course, because they won't follow the gold to gc ratio due to being random, but that makes for a nice gold sink. Some people could come out lucky and get 4999 gc which they could then spend on the items they really want, or they could fail and get 20gc, which can still be spent on items, just not the really expensive ones.