This is a post I meant to write after my first 'actual' kenjutsu class. Working with a skinken, or a real blade, has a way of reminding you to practice correctly. You work more slowly, cleanly. The fact that if you draw sloppily or hastily, you can cut through the saya (scabbard) should always be at the back of your mind.
It is similar to the way the Marines train as riflemen. We spent a lot of time working on safety procedures before we ever went live with a weapon. But, no matter how safe you think you are, it should always be in your mind that you are working with live rounds.
Clean and precise practice will lead to good techniques. Bad practice, quite frankly, can get you killed.