When you are first introduced to reactive power, you are most likely informed that: reactive power performs useless work and in many locations customers do not pay for reactive power usage; you are then shown the beer example, where reactive power is compared to the beer foam.
I think a better illustration is the iPhone storage, i.e. after purchasing a 16Gb iPhone 6+ and taking few pictures, you will soon realize that you ran out of space; at that moment, you realize that you only have 11GB or so of storage to use for your pictures/videos and apps, where did the rest go? Well, the 4-5 GB, which represents 25-30% of the overall space is usually used by the operating system, etc.; there is an ongoing lawsuit against Apple for using too much of the user’s storage for their latest updates. The attached picture clearly shows the issue: 11.5GB+12.5MB is way less than 16GB.
Hate it or love it, we need an operating system for our phones, computers, etc. Remember many years back when you accidently deleted a windows’ file and your computer went haywire, nothing worked till you reinstalled the same file or reinstalled windows again.
To better understand the importance of reactive power, learn about the impact of the electric system/grid when there is a deficiency of reactive power. Reactive power is like the glue that keeps the electric grid intact, since voltage is the potential difference, i.e. pressure difference, think of reactive power as the tool needed to maintain proper pressure. Adequate reactive power is extremely crucial during emergency events when a generator, a transmission line, etc. is lost.