Order Dual sim to use with S4a and SGearS ? topic

I'm almost owner of a Samsung Gear S thanks to buying a new TV ;)
Trying to be clever so i ordered a second SIM for this watch before it arrives. I ordered after phone contact with my provider a DualSIM card
But....is this the way to go? I'm not too familiar with Dual-SIM's. I know how those phones works of course but in two different devices that are connected in different ways?
Any feedback on this subject would be appreciated, maybe i can change my order if needed after reading your comments and/or experiences!
Thanks!