I am of the opinion that 10Ga wire on batteries is not just marketing hype. I think the 10Ga wire on the battery serves to conduct heat away from internal solder joints in the battery that have no cooling air flow. I do not think that implies you need 10GA elsewhere, because the Connector and ESC joints are not in a sealed container.

A racer at my track last weekend running 1/8th electric late model (basically a 1/8th buggy) with a 2650 motor melted the plastic case on his 4S pack that had bullet connectors. I personally would never use bullet connectors with that setup. I draw an average of 35 amps with a 2200KV motor, so I expect he was pulling more. I believe the bullet connector in the pack has no way to dissipate heat, unlike a Deans in open air. I think having the 10Ga wire on the pack reduces heat generated inside the hard case and so is of some value on the battery.