I figured it was something like that. Have you noticed any practical difference between the old and new device (aside from speed) or the results?
In terms of how the monitor calibration looks / its apparent accuracy, I have not noticed much if any difference between after calibration and profiling with my older X-Rite ColorMunki Display and my new Calibrite Display Plus HL colorimeters. So why did I upgrade:
(1) Future-proofing: the new top model will work with pretty much any display, including some 'new technology' models and models with internal LUTs, which mostly don't support the older model.
(2) Bargain: the new top model is normally $340, but I got it directly from Calibrite for $170. Sometimes the deal is too tempting even if the need is marginal.
(3) Reported performance benefits: over on LuLa some of the experts were discussing colorimeters, and at least one reported that when the newer X-Rite / Calibrite models came out that could e.g. support high-brightness / HDR displays, they
also produced more accurate results with 'standard' display. Just because my uncalibrated eyeballs don't notice much differences does not mean there's no visible difference.
(4) Potential benefits / flexibility from higher-end software: the older model uses relatively basic software, but the newer one uses more sophisticated software. There may be benefits from that, albeit not yet figured out by me.
(5) Device life: every device has some limited lifespan, either until it stops working, or at least until it stops working with peak accuracy / precision. My older device was not old, but was IIRC seven or eight years old. I can't assess the importance of that / predicted useful life, but it did occur to me.
All of that might not add up to much, and maybe it wasn't a wise expenditure. But I did it, and those are the reasons I did.