Sephora published its summer catalog in tablet form, but not in print.

Here’s some surprising news: consumers using tablets are more likely to buy, and often buy more, than other online or mobile shoppers. So if you’re on your iPad, you’ll spend more at Bluefly.com than you would on a laptop or phone. (Maybe all those lovely graphics account for this? Or it could just be that people who have tablets in the first place have more disposable income.)

No surprise at all, retailers are focusing their energy on the tablet-using demographic as the holiday shopping season approaches.

Though none disclosed exact figures, Macy’s, Abercrombie & Fitch, and Gap all reported that they saw their highest rates of conversion (browsing turning into an actual purchase) from tablet users.  Sephora makes equal revenue from tablet and mobile sales, even though the mobile site receives more visitors. This summer, the cosmetics giant experimented with dropping its printed catalog in order to offer it solely via tablet (they’ll continue printing other seasonal catalogs, however).

Of course, one reason tablet shoppers might be buying more is that they’re a group with disposable income. But other grounds for the positive numbers are specific advantages of the iPad and its ilk — touchscreens draw in and engage users better than, say, PCs, and the devices’ portability means more time spent online.

No matter the combination of factors that gets tablet users to spend, with data from Forrester Research indicating that a third of adults might own the device in some form by 2015, that high conversion rate is only going to get more important to retailers. And with Amazon imminently launching a tablet, those numbers might be something to watch even sooner than that.