How fast can you move from one place to another? Being able to move quickly is just as important as being able to continue moving over a long period of time and peed is one of the ten general physical skills we train.
Increasing speed is one part of increasing the intensity of your training session. Increased speed increases your work output. It's vitally important to increasing levels of fitness but there's a catch.
Speed without proper mechanics increases the risk of injury. This is why we constantly work our fundamentals. We improve our squat and press mechanics so that we can improve our speed, work capacity, and fitness safely.
I've written about this before but safe technique is efficient technique and is also has the capcity to be the fastest technique. The temptation is to try to increase speed before our technique is ready.
We're concerned with being fit for today, tomorrow and 20 years from now. This means you have the rest of your life to increase your speed and your work capacity. We just try to be a little better every day and then one day we'll wake up and be fiter than we ever imagined.