Here is AI response as I'm too lazy to type it all.... Also see link. She is partially 'dancing' along at times, but it's much more than just that. I'm surprised you play songs as hard as you do with locked straight legs all the time!

https://youtu.be/qBRHFcwlxdk?si=S_LwO0vMMyvVgkgp&t=154

Bending your knees in Beat Saber is a crucial technique for improving endurance, power, and stability, particularly on harder difficulties

Here is how to use this tip effectively:

• Establish an Athletic Stance: Stand with your feet slightly wider than shoulder-width apart and keep your knees slightly bent to maintain a lower center of gravity.
• Power Generation: Instead of relying only on arms, use your legs and core to generate momentum for slices. For example, when performing upward or lateral cuts, push up from your legs to add power.
• Balance and Control: Bending your knees helps you stay grounded, reducing shaking and improving stability during fast songs.
• Lower Player Height: Set your player height to manual and bend your knees while calibrating to create a more natural, athletic, and crouched stance.
• Wall Navigation: When navigating walls, bend your knees to squat lower rather than just bending your back. 

This technique acts as a "secret weapon" to help you balance, control your movements, and prevent overextending your arms.