When it comes to training, it's important to work your supporting and stabilizing muscles just as you work the ones that give you the gains you're working for. Your external rotation cuff is the group of those stabilizing and supporting muscles that keep you safe as you get stronger.
Your rotator cuff is like the brakes on your car. If you have good brakes, you can floor it and go fast because you know you can stop quickly too. But if your brakes are poor, you have to keep the speed and power of your car at a level your brakes can manage. If you don't, injury can occur. The same applies to your rotator cuff. A strong and powerful rotator cuff means you can push, pull, punch, and throw fast. Weakness in the rotator cuff means these can be slow and weak or even worse, painful.
Now on the other hand, the benefits are that if your rotator cuff is strong, your body will allow you to gain strength easier in other places because you have the right strength in your "brakes". It's like when you developed some maturity and your parents finally let you stay out past 9PM. (For some of us, that still hasn't happened and rotator cuff work could help that too)
Now for someone who is more of a beginner, it's not appropriate to toss them onto a hard rotator cuff exercise like a Cuban Rotation with a barbell. Instead, we start with something supported like an Elbow On Knee External Rotation. This movement let's you work the rotator cuff in a way that is suitable for newer trainees.
Im doing a set on each arm in the video here after my straight arm strength session.
Strengthen your rotator cuff so your shoulders remain safe as you train and gain!
Check the IG stories for info on rotator cuff training!