@Hooked, Seems the idea is that you charge your 18650 in the charger. Once charged and left in the charger you can then use the device to charge something else from the batteries you charged in it. It is thus a power bank that stores it's charge in user replaceable cells.
@Raindance Ah! Now THIS is a clear explanation. Thank you!
But it still seems awfully cumbersome to me. For example, I'm going out and about with my mod. Before I go, I must charge the batteries (in the XTAR or elsewhere). Then off I go with the XTAR and the batteries still in it. My mod runs out of power, what to do? Now I must plug my mod into the XTAR in order for the batteries in the XTAR to charge the battery in my mod.
Right now, if I go out I just pop spare batteries in my bag or pocket and off I go! Mod runs out of power, I just replace the battery. I don't need to connect to yet another device which I have to cart around.
In terms of the charging time, sure it can and indeed will charge a couple of 1500mAh 18650's in a very short time. Charging time will also be affected by the supply current. The charge time when plugged into a 1A power supply will be double that of using a 2A supply. If stated performance was based on charging two 2500mAh cells on a 2A supply and you are charging two 3000mAh cells on a 500mA supply from a PC USB port results will be very different.
I didn't charge it from a PC. I charged it via a 2V USB plug, plugged into a wall socket.
Regards