The po-int of the posters as I see them are to make ATCOs think a bit about the speeds they use to stream aircraft. So many people start at 300kts+ and work backwards in 10-kt steps. This may require the one in front to speed up from its Econ speed for no real reason other than a lack of awareness. If you start at 280kts or so then you can achieve a stream just as well and save fuel at the same time.
In addition, many ATCOs seem automatically to use 10kt differences between subsequent aircraft. Notwithstanding the slight differences in TAS as the ones behind are a few thousand feet higher, it is perfectly possible to achieve a stream of aircraft with them all flying the same speed. Speed control to create extra miles does not work on the majority of UK en-route sectors as the distances are too short. It does a good job at stopping them catching up with each other too quickly, though.
Here's an idea: put the information on the posters into your back of tricks and use it now and then. You might find you can still stop the aircraft bumping into each other, provide good presentation to the next sector AND save the planet at the same time. Can't be bad, can it??