First and foremost, there is absolutely no reason to buy furnishings because there is absolutely no reason to be in a guild in the first place.
Why? Three Reasons.
0. You have to pay for every last thing in the guildhall, which means that your progress will be cut down to size by paying into your guild if you're just starting out. Having veterans to pay for it would be a must.
1. It doesn't actually help you branch out or find a group of friends most of the time. Going on runs and joining randoms and then friending them is just as good as joining a guild. If you aren't over ambitious and make friends gradually on the content you can do, you'll become a veteran with veteran friends in some time. Joining a guild can be nice help on levels, but getting carried through the game by veterans is pathetic.
Any existing friends that you start the game with already know you and can communicate via steam or even through the SK chat. Forming a guild with them would be cool, but the chances of one of you quitting are enormous, and there isn't any benefit to having a guild.
2. None of the features benefit you at all. Guild training? Just go to EoS or whoever has it open. Krogmo in the guild hall? Why do you even care? Owning a statue of the snarbolax? I mean, it looks cool but IT DOESN'T DO ANYTHING.
What people wanted
This:
http://forums.spiralknights.com/en/node/40011
is a link to Severage's thread. Severage documented pretty much everything suggested about guilds before the update was made. Severage, and all the other contributors to her thread, imagined guild halls a bit differently than they came out.
The biggest difference, was that Severage's guildhall wasn't based around fixing the in game economy or purely showing off to others. Players could choose to donate crowns for upgrades, but these upgrades were mostly non-cosmetic, and were designed as a way to bring people together as part of the guild. Severage did mention prices but the highest one was "Display Cases (Shadow Dungeon Bosses) 75,000 Crowns, 800 CE" which is nothing compared to what you have to pay to get the current boss trophies and more importantly, actually required beating the boss.
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TL;DR
Radiant Fire Crystals are in high demand and that makes OOO evil.
Players want to customize their "living space" the same as they customize their armor. Players can buy all the accessories they want, but it won't make them better players. Guilds want to customize their halls because it's fun and looks nice, and if they're recruiting, then to attract potential guild members.
Empty guild halls and accessory-less armors don't scream "I'm unique" as much as guild halls with furnishings and fancy accessories.
Graveyard edit: Well jeez, I didn't even make my response in time.
Undead edit: Well apparently I left and came back and this thread is alive again. Go figure.