Hello. No special reason really.Is there some reason why they aren't supplying L*a*b* or spectral CGATS files for these colors?
Designers typically do not work with LAB or concern themselves with what CGATS files are. They however need to know which ICC profile to use when setting up their CMYK files - that would include SMS colours.
If you are interested in checking out the LAB values of SMS colours you can of course check them out yourself if you open the sRGB labelled patches in Photoshop and hover over the colour(s) of interest. Those are the LAB values or extremely close to the LAB values you should be able to hit in CMYK printing, analog or digital.
The SMS colour palette concept is an attempt to get Graphic Designers away from using amazing, media relative colours that most Printers can't actually produce, - but instead to get into a new mindset and up and running using a decent number (2.607 colours) of common colours that any Printer should be able to reproduce and at the same time getting Designers aquanted with proper ICC colour management and how to use it correctly to manage their brand colours (or have them managed by Spot-Nordic) for all media (Print, Web and TV), - and at the same time to help create a reason for Printers to at least be able to print to ISO 12647 standards when requested - with an accuracy of DE2000 of 2 or less preferably, - 3 at the very most to be able to say that the target colour is at least visually very similar to the printed outcome.
SMS colours request this of Printers and since they are solid colours printed in CMYK there is no way for Printers to get around this or "winging it" by selling the job with "pleasing colour" and a charming Printer giving a speech about what is possible and what is not.
Any customer can check the LAB value of his or her SMS brand colour with a simple i1Pro2 spectro.