Bluetooth Low Energy (BLE) was first added to smartphones in 2011 as part of the iPhone 4S. Since then it has become the de-facto way for smartphones to communicate with external devices. While BLE was initially intended to send small amounts of information back and forth, today many applications stream large amounts of data, such as sensor data for tracking steps, binaries for firmware updates, and even audio. For these types of applications, the speed of transfer is very important.
This is a companion discussion topic for the original entry at https://interrupt.memfault.com/blog/ble-throughput-primer