It isnt more effective
Arguably it's less effective, as it leaves parents under the false impression that something useful has been done.
And yes it requires education, of both parents and DC. Parents so they can use blockers as effectively as possible, and DC so they understand why porn (and other harmful content) is wrong.
Yes, blockers can be circumvented, which is why supervision is still needed as well.
And even if some find it a PITA to set up blockers, that doesn't alter the fact that using them will do far more than this measure to put an age verification regime onto five (yes just five) well known and easily identifiable porn sits that blockers wouid block anyhow along with hundreds of others