True, the verse does not suggest NFP. But it supports and harmonizes with NFP because it says mutually consenting, prayerful, periodic abstinence can be a good thing.
This is something Scripture never said about contraceptive paraphernalia.
And yet there WERE different types of such "paraphernalia" even back then (see https://en.wikipedia.org/wiki/History_of_birth_control). Since we know that the Scriptures teaches all things related to our salvation and godly living, wouldn't it be sufficient to cover that topic with God's warnings against adultery, sexual immorality and murder?
Except that NFP isn’t about not having sex for the purpose of prayer.
It’s about trying to avoid procreation by other means than barrier methods for the purpose of being able to have sex without being open to procreation, which is what Catholicism condemns.
Catholicism, in many ways, and some very subtle, condemns sex, especially sex for the pleasure of it, as if it’s something degrading and beneath the dignity of humans, especially the “spiritual” and “holy” ones.