Well clearly I didn't say the sole purpose. I gave both and I explained their complementary nature, one feeding the other, the other feeding the first.  

Yet the procreative, as Pius XII pointed out, is most God-like; the will cooperating with God's will overflowing in new life.  We participate in God's own creative capacity, with our Yes, our will. 

Procreative also in a very substantial sense "generates" more ongoing demands for holiness and self-gift on each person of the couple; it involves greater and ongoing "yes" to love.    More sacrifice, more denial, more acts of charity, more overflow into the family. 

Trinitarian. 

Many people have never heard of such things before, and they will demean, defect, dismiss, besmirch them, not out of knowledge but out of ignorance. 

Mary's fiat.  We get to imitate her Yes to God in procreation.

In this sense procreation is an act of even greater union than marital embrace closed off to life. 

So procreative is higher.