If we're talking about digital forensic tools, which is what we're talking about in this context, they can be used to acquire digital evidence, recover deleted files, analyze files of interest and create a timeline of interests and events. They almost always require the physical access to the device.
That's the distinction between what is spyware or ODITs, where you could do that remotely, without the knowledge of the individuals. They're different tools, but they still nonetheless have important capabilities.