The only tactical advantage I've found so far, is
a) If you have Mining Facs inside the Asteroid Field, you can defend them with Corvettes and Bombard Ships, and hit their ships long range, whereas they're forced to send equal sized ships after you or else take the lengthy process of manouvering close to the field.
Or
b) If the enemy isn't watching, you can lure his Accas/Frigs into a field with your Corvettes. Sometimes I strike Accs with Gunships and Corvettes, stand my ground, wait for the enemy to target them, and then get the player's attention elsewhere. If you're close enough to an Asteroid field, you can lure his cruiser in. Of course, he'll get the warning, but hey, it's a little bit of damage that might make a difference in a close fight.
"we have an agenda, a character assassination agenda, assassinating characters is what we do for a living" - Sukkit