Sony says you shouldn't use the Xperia XZ1 and XZ1 Compact underwater, despite them being water-resistant

Earlier today, Sony announced two new high-end, dust- and water-resistant phones: Xperia XZ1 (pictured above) and Xperia XZ1 Compact. Even though both handsets are IP68-certified (which normally means they should survive underwater for 30 minutes at depths of up to 1.5 meters), Sony says you "should not put" any of the two phones "completely underwater."

Here's exactly what Sony states about the water resistance of the Xperia XZ1 in a footnote on its official website (also valid for the Compact):

"Xperia XZ1 is water resistant and protected against ...