It's misleading, since it sounds like everywhere is just going to be a tiny bit warmer, basically unnoticeable. However, it's really about the massive amount of energy required to warm the atmosphere up by that much, and how that energy isn't equally distributed.

One analogy I use is: imagine sitting in a pool with friends, and one person starts pushing one of those floating lounge chairs up and down. They might only increase the average height of the water by a millimeter or so, but the whole pool starts getting more wavy and chaotic. That's how it is with our atmosphere - more extreme events (both "hot" and "cold") occur and in general more chaotic weather as that energy is spread in waves and troughs throughout the world.