What is the primary purpose of aggregation in MongoDB?

The primary purpose of aggregation in MongoDB is to analyze and summarize data. Aggregation operations process data records and return computed results, allowing users to perform complex transformations and calculations on their data sets. Through various stages and pipeline operations, such as filtering, grouping, and sorting, aggregation enables users to generate insightful summaries, statistics, and reports from their data collections.

MongoDB's aggregation framework is particularly powerful because it can handle large volumes of data efficiently and allows for a wide range of operations like calculations, data transformations, and grouping, which are essential for generating meaningful insights from the raw data stored in databases. This makes it a vital tool for data analysis, reporting, and business intelligence.

The other options provided do not align with the fundamental objectives of aggregation. For example, deleting unnecessary data pertains to data management rather than summarization, creating indexes is aimed at improving query performance, and speeding up backups involves data storage and recovery mechanisms, none of which directly relate to the core purpose of aggregation in MongoDB.