Ask anybody on the street, the alternator is a magical instant battery recharger providing free energy anytime the vehicle is driven. Why all you need to do after a jump start is required drive around the block, once, and the battery is now magically full!!
And if you believe this, you should do the world a favor and let these same people perform heart surgery on you, while watching your children and pets, and sign over power of attorney to them as well.
12 volt ciggy plug outlets are horrible, unreliable connectors. Just because they are widespread and ubiquitous does not make them adequate or just fine desirable, or any other positive adjective.
They waste power and they waste more when they are asked to transfer more electricity through them.
And let the 'Just fine brigade' come out of the woodwork with their tales of longevity, perfection, and magical properties.
Ciggy plugs are junk. Ubiquitous junk, and if they are asked to pass more than 6 or 7 amps regularly for any duration, they will fail, and can fail disastrously, not just inconveniently.
Fuses are not cheap, and a worn ciggy plug causes lots of voltage drop. the more voltage drop, the more amps that have to flow for the required wattage to reach the device. More amps cause more voltage drop, causing more amps to be required to flow and on and on until something melts.
Something will melt. It is just a matter of time. Hopefully it is just a fuse.
Anybody using a heating device with a Ciggy plug attached, if they were to cut off the ciggy plug, and hook it right to the battery terminals, the time required to heat the material to the desired end point would be significantly decreased, and less energy would be consumed from the battery to accomplish this.
If however you like to heat up copper wiring and fuses and springs and steel contacts instead, and use more battery power to do it, by all means surround yourselves with Ciggy plugs and receptacles and start your "works just fine" chant.
Perhaps somebody else will believe it too and justify your thinking.
They want to believe it.
This task will be easy.
BTW, my Van gets 35MPg city, its exhaust smells like fresh roses, and my local electric company constantly pesters me to hook my Ciggy plug inverter to the grid to power the city and avoid rolling blackouts, they even offer to pay for any increased gas usage from my magical alternator, which also farts a special type of collectable fairy dust which when concentrated, can illuminate sporting event venues, and cure erectile dysfunction too.