Titanic Knurl and Planula seem underwhelming?

How are these two items classified as boss quality?

I did not test Planula all that much but the few times i had it it seems irrelevant compared to white and green quality healing items.
Titanic Knurl honestly feels worse than a green quality item, i really do not see how it can compete with other Boss quality items.

Wikiepedia says Knurl flat health regen scales with player level but its so small that its meaningless even at very high player levels.
What do you fellow players think of these two items?