Notice I recommended a relay, not an isolator.
And an added resistance in the circuit, such as an isolator, is not the same thing as a parasitic drain. The resistance added by an isolator only adds to the 'work' on the circuit/batts when current is flowing, a parasitic drain will always be there.
If your setup works for you, more power to you man. Again each individual situation is different, and you might get away with it just fine. But people should understand the situation before making their choice, so they can make an educated decision.
Cheers.