Charge Fitbit charge 2 to the power?

Re
1

I gave my mother a Fitbit Charge 2 for Christmas. A charging cable is included, just not a power supply. In the manual itself is that one should load the clock over a USB haven thus laptop etc. I think that's pretty awkward. Can I charge the clock with a clear conscience with my Fast Charger or a normal Samsung power supply or rather always via USB?

Ba

I also charge my Fitbit directly to the power outlet via USB power adapter. Can you or your mother do it this way?