The extender is simply a device that duplicates and rebroadcasts your already existing Wi-Fi network. Its primary purpose is to extend the signal range.
While the choice between the eero Beacon and the eero Extender boils down to your needs, we recommend you go for the Extender instead of another eero Beacon.
It allows the range of the network to reach more people, although with a slight reduction in network quality. Extenders can also be easily installed without any technical knowledge.