If it didn't matter, Honda wouldn't take the trouble to run a dedicated winch ground on the 2017 models back to the motor.
That's just a convenient spot to ground a winch (without a second battery installed) while not having to jack with more connections to the stock battery. Honda doesn't expect everyone to have a dual battery setup. It's all 6 of 1, half-dozen the other either way. I'd just prefer a shorter wire back to the "actual" ground which happens to be the negative terminal of the main battery.