1. It is very readable, IMHO the most readable of all languages.
2. It has the most useful higher-level, generic data structures built-in, e.g. dictionaries, lists, sets.
3. It is interpreted, which is the only way to make exploratory programming comfortable. Most useful for learners and scientists.
4. Its late binding data type safety makes ad-hoc programming less painful and encourages the use of tests when production readyness is needed.
Of course, Python is not perfect. I e.g. would appreciate immutable-datatypes-first and a more functional centric approach. But one can lament about everything.