Also, according to the article, "high-density compute nodes feature a heterogeneous CPU architecture" which is needed for "green computing-type systems (e.g. network and storage systems, cloud computing or large-scale data centers)". I have no idea what that means.
High-density compute nodes are a specific type of processors that have manycore CPUs. The reason they are called high-density is because they pack tens or hundreds of small CPU cores onto a single die. These types of small cores don't provide massive single-threaded performance by themselves but when added together, they can be quite compelling. This is a different approach to having a few but very powerful cores such as Intel Xeons on an SoC. An analogy would be a flock of starlings versus an eagle. Moreover, many CPU designers today have abandoned the practice of scaling in frequency to achieve performance and are focused more and more on performance per watt (hence the term green computing). This is because the costs associated with powering and cooling a data center are rapidly rising.
Because when I think "IoT", the first place I think of is a datacenter...
IoT == "connected devices"... with the emphasis on devices. i.e. embedded microcontrollers.
Also note that they themselves don't have to be packaged with some RF comms, plain old microcontrollers are entirely suitable for most cases.
Exactly why a guide would be useful to help understand the tradeoffs... which this guide does not supply.