Somewhere there is a better post (got bookmark overload) - how Dual’s use EMMC for local storage if using CloudDVR similar as described.
How to migrate to a bigger drive? - #87 by TabloTV
USB Flash Drives... now supported - #3 by TabloTV
If a user uses CloudDVR …or has no drive attached, these devices, presumably moving forward, are designed to handle live TV buffering for pause etc locally.