Signal and Wait for Signal

What is the difference between the *condition* "System: on signal X" and the *action* "System: wait for signal X"?

In other words, where should we use "wait for signal"? Can you give an example of "wait for signal" proper usage?

If i use it inside a set of actions and the signal never arrives, what happens with that block of code? Potential bugs magnet?

I actually never realized there was "On signal" condition!

There is no right or wrong, you can use either the condition or action, whichever is more convenient for you. If the signal never arrives, the rest of the actions after "wait" will never be executed. Don't think this can cause any problems.

I was also shocked to find this Signal thing, it can decouple code and I wonder why people dont use it regularly.