There is some things you aren't considering. First off, is the ability to swap that fuel rod out for a freshly charged replacement at any time, as many times as you want. The generic charger from Wal Mart may be almost double the capacity of one Fuel Rod, but I can swap that 2, 3, 4 times a day if I need to (and I have) for a freshly charged unit. So, effectively, that gives a Fuel Rod 2, maybe even 3 times the capacity of the generic charger from Wal Mart.
There is something else to consider though. A Lithium Ion battery has a life span of about 500 charge cycles. After that, it is junk. If you are using it daily, you can reach that point in well under 2 years of actual use. Even if you aren't using it that often, the battery still only has a life span of 2 to 3 years, and if it spent a year in warehouses etc. between the time it was manufactured, and the time you bought it, you could possibly only realize 1 or 2 years of real life out of it. I know this to be true, as the last generic charger I bought lasted exactly one summer. Turns out, it was well over a year old when I bought it off
Amazon.
The Fuel Rod also has that lifespan limitation, BUT . . . when it no longer works, guess what . . . you can swap it at a kiosk for one that does work, and continue using it, and for as long as the Fuel Rod company continues to exist, you can continue to do this, meaning that your Fuel Rod has the potential to outlast the generic by many many years. Assuming that this company stays around for 6 years or more, the Fuel Rod has the potential to be a much better value.