As good as Google Wallet might be for payments, you've so far been locked into using one Google account; that's not so hot if a family member needs to borrow your phone to send some cash. That won't be an issue after today, since Google has updated Wallet's Android app with a tweaked interface that lets you use multiple Google accounts. You'll also get shipment updates for orders from distant retailers.
There's also an under-the-hood upgrade that should affect other apps you use. A Google Play Services refresh makes it easier for developers to put Google Wallet Instant Buy buttons in their titles; when they do, it'll be trivial to buy something on a whim. That's not great news if you're an impulsive shopper, but we suspect that those with a good handle on their finances will be happy with the improvements.