Balance: $0.00
Inventories can hold thousands of items, so they aren't loaded automatically.
BUFF-style flow: when your item sells, the site sends the buyer's offer automatically and you have 24 hours to confirm it in Steam Guard. Confirm in time and you're paid (minus the 5% fee); miss the window and the sale cancels and the buyer is refunded.
Needed so a buyer's offer can be sent to you automatically when your item sells.