Imagine a scenario where you have to perform some sort of processing then persist information to RDBMS. Without the support of sequence numbers in the underlying RDBMS, support, you have to perform these tasks in a serial fashion.
As you can see from the following diagram, it is very easy to make your overall process to run in parallel
I have not used this in any real project yet. When get a chance to do it, I will update this blog further.