Just for completeness, below are the relevant links and screenshots.
It would be good to have an official statement explaining the changes but also it is interesting to note that the SPU/SecurityPower does not appear in the latest chart for all but the Scalable Platforms (44k and 64k) and the 1400 series appliances.
Current Appliance Comparison Chart:
https://www.checkpoint.com/downloads/products/check-point-appliance-comparison-chart.pdf
Current Appliance Brochure:
https://www.checkpoint.com/downloads/products/check-point-appliances-brochure.pdf
OLD (dated October 24, 2017):
NEW (found online today (19 Dec. 2018)):