Hmm, let's see. If I buy a marine group 24 battery, I have to take it out and hook it up to a battery tender. Then I need to pick up an air compressor. To charge my laptop, etc., I have to get an inverter and hook it up to it. Then I have to deal with switching the inverter wires, jumper cables, and battery tender wires.
With my Wagan, I plug it into the outlet in my RV. When my RV is on shore power, it gets charged up. If I need to jumpstart, I just unplug the power cord. When I want to charge the laptop, phone, etc., or play my music, I just plug the device into one of the two 12 volt plug or one of the two 110 outlets on the Wagan.
I guess it makes me a dummy to see that I get a lot more flexibility for the money than I would with a loose battery.