The ciggy plugs that come on most appliances are quite poor.
Seems the blue seas 12v receptacle design has been well copied. I'd still not ask them to pass more than 4 to 5 amps on a continuous basis.
Try pulling out the plug after passing 5 amps for a minute. When that spring loaded nipple tip starts getting hot, and it will, think about having a backup ready to install.
The blue seas plug is a fairly good design, and one can get 12AWG under the screws inside the plug, but might have to modify( drill out) the tailcap to allow 2 12AWG wires to exit.
I've switched to Anderson powerpoles for all 12v connections. not as convenient and no internal fuse, but I can trust them, and not worry about horrendous voltage drop and inevitable failure.