I hardly ever use spawn points unless I have a lot of low mana cost creatures in my book and I'm running a swarm. When I see a spawn point come out I immediately change my turn order to account for in advantage in summoning that my opponent has. Though, depending on when a spawn point comes into play also in a big thing to pay attention to.
If a Mage brings in a spawn point early game, then I assume they are going to be swarming with a lot of creatures and I have to destroy that spawn point as soon as possible to cut down his/her summoning potential. Or I have to block the summoned creatures in the zone they are summoned in so I have a few rounds to take care of the creatures, whether through DOT damage or attacking walls.