To Sticking With It with anything, it first has to be easy to do. It also has to work well. Zone 2 training meets both conditions.
Zone 2 training means running for a long time at an intensity where you can still hold a conversation. I try to go for at least an hour. Intensity is sometimes measured by heart rate, but heart rate shifts on days I've had caffeine and with how I happen to feel that day, so it seems hard to use as a standard. Anyway, I consider it proper zone 2 if the intensity is low enough that I could do the same workout again tomorrow.
The biggest reason people fail to stick with exercise is probably that the process is painful. Zone 2 training, though, is by definition an intensity you can do again tomorrow, so it's easy to maintain. The low intensity also means less risk of injury.
It gives the body a moderate boost of energy, so it also works well as a routine to start the day. I began doing zone 2 runs every morning during my month living in Bali.
The most representative effect of zone 2 training is an increase in the number of mitochondria. This helps improve endurance. The number of mitochondria is determined by exercise volume, and because zone 2 is low intensity, you can sustain it for a long time and so build up a lot of volume.
Aerobic exercise is also very important for the physical fitness of knowledge workers, so it needs to be kept up consistently.