"Recursion - Allow process to evaluate a record multiple times in a single save operation?" what this mean in Salesforce process builder?

https://help.salesforce.com/articleView?id=sf.process_advanced_considerations.htm&type=5
This post has some examples. Worth a read.
This is what I gathered:
If you have a process builder that is set to fire when "a record is created / updated",
And in the actions, you are actually updating a field on the same record,
When a new record is created, it fires the PB the first time,
Then a field gets updated and the PB fires for the same record for the second time.

This is powerful and dangerous at the same time. The design considerations mentioned in that post are worth considering!