Actually I wouldn't dismiss that so easily. True is, that there are not much virusses, trojan and the like out there that affect Linux-based devices. But there is still the possibility that someone hacks the device while its connected to the internet, especially when its connected via unprotected wifi. there are even exploits for bluetooth.

But compared to a windows device the tablet can be considered quite safe, so the correct answer would be: Probably not, as long as you keep your wifi protected with at least WPA encryption and set passwords that cant be easily guessed.
If you have no intentions of hacking/coding for the device, it'd probably be a good idea to shut down the ssh server running on the device and also to keep the device in offline mode when you're not actively connected to a network.