That about sums it up for me as well. The battlefields are readily available merchants who have good loot on occassion, and there's some easily available loot to scrounge if you like butchering monsters.
I'd argue that it's a cheesy way to avoid game balance, but the monsters level with you on and off the battlefields, so it really doesn't make *that* much of a difference if you go and thump monsters or not. I did religiously in Act 1, I haven't bothered at all in Act 2, and probably won't. Really, it's a boring place to blow off quest steam and kill stuff for bucks.
The big advantage it has, to me, is that it's immediately available merchants, unlike in Divine Divinity, where good merchants were only avalible in Ars Magicana. I had to park one of my teleporter stones in Geoff the Blacksmith's shop so that I could conveniently dump off goodies to him; now I can use the teleporter stones as I want to, and use the battlefields to throw loot around and store gear.
I'm glad they're there, I just never see myself actually PLAYING in them any more.
yup, I just use them for merchants, nothing else.
