Sony made some tweaks to its design aesthetic this year to accommodate the inclusion of a fingerprint sensor in the power button of the Z5. It's not as accurate as I'd like, but it's still nice to have. However, a number of reports claim that Sony will not include this feature in the newly announced US variants of the phone. We reached out to Sony and got confirmation: no fingerprint reader for the US.
A fingerprint reader is still listed on the Z5 Compact spec sheet (not Z5, though), so perhaps this was a recent decision. In the photos of the US variant, the power button does look the same as the international version, which definitely has a fingerprint sensor. When we asked about the lack of a fingerprint reader, Sony told us, "This was simply a business decision."
Sony is launching the Z5 and Z5 Compact in the US next month for $499-599, but they've been available internationally for months. In fact, the international SKUs are available on sites like Expansys and Amazon for less than Sony's retail price, and they have fingerprint sensors. I'm just not sure why you'd buy the US version now when it's a little more expensive and it lacks a fingerprint sensor.