It would not surprise me if this is part of the streamlining effort they're undergoing in the run-up to the 2020 Olympics. They've already added those machines to do the fingerprinting and photo before you get to the Immigration officer. At first I though the passport scan at Customs was going to slow things down, but perhaps its there to speed things up: the officer has to ask fewer questions as the computer can advise on things like travel history, time out of the country (for residents), and country of origin for the inbound trip. Those used to be done by flipping through the passport pages and asking questions.