Honeypots

That would, in my view, mean I shouldn't take the map as accurate.

What does "accurate" mean? It's not comprehensive - what it does is show you where their honeypots get the most attacks from over time.

That said, it's not all that useful - there's no shocking information here. As mentioned, it's largely a marketing tool.

Correct. But you could do a pretty good idea with some honeypots (customers) and a few agreements with ISPs to see where similar packets go.