Redis Streams are a data structure in Redis that can efficiently handle time-directed and immutable data streams, such as those generated by IoT devices, making them suitable for the initial ingestion of large amounts of data. Redis Streams offer flexible data modeling options, allowing multiple instances of the same field to be present in an entry, which can help reduce storage space. The use of Redis Streams can lead to significant savings in overhead when dealing with large datasets, as demonstrated by a hypothetical example of 1 million entries with 20 fields each. The key benefits of using Redis Streams include constant-time access to entries and the ability to compress index IDs using a radix tree data structure. Additionally, Redis Streams allow for space-saving mechanisms such as storing only unique field names.