Being able to read other people's tells is a useful skill. It makes you a better negotiator, salesperson, and competitor in sports and games like poker. But, in more collaborative environments it's good for the people around you to know your tells.
It's often a big relief when your team knows to help you before you even need to ask (e.g. when you're nervous or tired), or when your friends understand that you're acting strangely due to stress or other circumstances. Knowing each other's tells helps bypass the need for uncomfortable conversations, which is better for everyone. And further, when people know your tells, they can be more confident that you are being completely honest with them.
While your tells may be vulnerability in some settings, sharing them can also strength relationships. How many of your friends know your tells?