Prioritization is the essential skill you need to make the very best use of your own efforts and those of your team. It's also a skill that you need to create calmness and space in your life so that you can focus your energy and attention on the things that really matter.
It is particularly important when time is limited and demands are seemingly unlimited. It helps you to allocate your time where it is most-needed and most wisely spent, freeing you and your team up from less important tasks that can be attended to later or quietly dropped.
With good prioritization (and careful management of deprioritized tasks) you can bring order to chaos, massively reduce stress, and move towards a successful conclusion. Without it, you'll flounder around, drowning in competing demands.