NGL (and I only have dm experience in 3 modules with a handful of players so take with a large grain of himalayan pink salt mmm) - I generally use mages and counterspell specifically to discourage lazy play. Blast the last 4 cultist encounters with fireballs? Oh man is there a counterspell ready caster in the next lol. Midlevel bosses and BBEGs aren't dumb, they know magic exists, and they'll retain talent. Letting that talent show illustrates the stakes, as well.
But I don't use it to counter healing or well role-played hijinks.