It absolutely is a thing.
In hindsight, it would appear obvious Rouge could only endure her prolonged pregnancy because of PoL.
Vegapunk outright speculated Kuma managed to protect Bonney because of it.
Thriller Bark which has never been more relevant, also had a striking example.
I'm sure there are other instances we can speculate over, but the bottom line is that PoL is a real part of One Piece and has been for a very long time.
Fundamentally, I don't think PoL is Conqueror's Haki, but a lot of Conquerors have it because they have powerful wills that extend to those they love. I don't think Rouge or Kuma had CoC but the unyielding love of a parent for their child.
Sanji will likely awaken CoC and PoL will be what allows him to achieve feats with Haki others can't - like destroying lasers.