[noggin]

Does it even make sens? I mean, price per GB in SD cards are pretty expensive compared to traditional magnetic HDD.
Plus, you cannot have more like 256GB SSD card, which will be pretty expensive.
Plus plus, it will wear out pretty quickly (in terms of lifespan).

Why don't consider external HDD with USB cable or SMB/CIFS share via NAS or even normal desktop PC?

 The only reason I can think of for using a uSD card for media is if you want to use the same storage in your C2 and an Android or Windows tablet (or Android phone) to watch/listen on the move.  (I have a small library I keep on a uSD card for that very purpose)