if I HAVE to do that, I WILL forget it occasionally (just like I sometimes try to winch now before I remember to hook it up) and that seems a very stupid place to put myself in. Not to mention I have an intermittent phantom draw in the truck, and insurance against that would be nice - I don't get that with a direct hookup.
If I go with the trailer battery, I think it's smart money to spend 2 bills on what's actually a pretty high end charger that should keep that battery in tip top shape for years of abuse as long as I don't draw it down to DEAD and kill it.