MostlyIt's mostly psychological - purchasing a home, furnishing it, etc. gives you a sense of belonging - to say nothing of no longer needing to pay for rooms by the night - plus a great and secure place to dump all your stuff: my house is full of helmets, steel boots, furniture, food, torches, books (on bookshelves).
Having leveled up to 38 and reached 100 Enchanting and 100 Alchemy and 80 Speech I am about to build a full set of invincible armour with which to go questing. The process to get to 100 Alchemy, Enchanting, etc. is well documented elsewhere and I made 150,000 goldGold in the process. And all this after about 4 days of playing...