From the article, the design “mimics the look and feel of a PalmPilot to keep it simple and familiar for IMAX film projectionists”

To skip operator retraining? At least that's how I read team "it's only look and feel, not an emulator". My objection to that would be that a hypothetical outcome of a modern UI with identical menu layout not being good enough would be one of those things that you only ever learn the hard way. But who knows, perhaps it was a new UI that was vetoed out by someone in a very powerful position and then they had to skin it up. But the far more likely explanation is that they had software, were running out of hardware devices to put in projection time until someone tried their hand on running one of the numerous palm emulators in existence on an RPi or similar.