All blessing, regardless of who gives them, come from God.
That being said, from my first instruction as an EMCH, I was instructed to bless babies and young children as they come with their parents to Communion. The blessing I give is a simple hand on the head, thumb blessing like I received every morning from my mother as I left for school. The words I use are “may the Lord bless you and keep you.”
I am not a priest. However, I do act on his behalf. So you could say that God blesses through the priest who in turn blesses through me.
I now belong to a more conservative diocese than where I was first commissioned as an EMCH. It is the first place in which I have seen adults come forward for a blessing. These adults, for whatever reason, cannot receive Communion. Individuals on the other threads within this forum have stated how this simple blessing helped them make the decision to join the Catholic Church. At the same time there were many posters who were vehemently opposed to the practice. My position is that I am being obedient to the priest who has directed me to bless those who step forward for this blessing.
Blessings are a sacramental, not a Sacrament. There is always the pastoral consideration.