By all means, if you're not using the functionality, I'd recommend disabling it. However, if you want to clean up that data, you need to make sure that happens first before disabling otherwise you won't be able to clean up that analytics data.
There is a scheduled task called "Remove analytics data". You'll want to edit that task and change the "Task data" value to 540 days, then manually run it. Then go back in, edit that task, change the value to 360, then manually run it. Then go back in, edit the task, change the value to 180 days and manually run it. Finally, go back in, change the value to 0 and manually run the task.
After you've run the task with 0 days, there should be no analytics data stored. You are then safe to disable analytics.
Now if you find you really need that data then maybe you want to take a backup of the database OR just leave it in your database, it's up to you.