Materialized View vs View
When you need performance on data that don't need to be up to date to the very second, materialized views are better, but your data will be older than in a standard view.
While creating Materialized view Oracle creates two objects, a table where the results are actually materialized and a materialized view that has all the metadata (the query, the attributes, etc.).
But while creating View Oracle creates only one object, which has all the metadata(the query, the attributes, etc.)
You use materialized views for performance reasons mainly.
According to the Oracle docs:
A materialized view is a replica of a target master from a single point in time.
A regular view loads data 'on demand' and can 'automatically' change when the underlying data changes.
A materialized view is a database object that contains the results of a query. They are local copies of data located remotely, or are used to create summary tables based on aggregations of a table's data.
Materialized views, which store data based on remote tables are also known as snapshots.
A materialized view can query tables, views, and other materialized views. Collectively these are called master tables