What is the advantage of using Handoff between devices?

The advantage of using Handoff between devices is that it allows users to start a task on one device and pick it up seamlessly on another. Handoff is a feature that enhances productivity by enabling continuity across Apple devices. For instance, if you begin writing an email on your iPhone, you can easily switch to your Mac and continue composing that same email without losing any progress. This smooth transition is facilitated by Apple's ecosystem, which maintains context and state across various devices as long as they are logged into the same Apple ID and meet the requirements for Handoff.

The other options do not describe the primary function of Handoff. While battery life and internet speed may be considerations in device usage, they do not pertain to the Handoff feature specifically. Unlocking devices with Touch ID is a different security function that does not relate to task continuity or transitioning between devices. Thus, Handoff's primary benefit revolves around efficient workflow and seamless task management between devices.