Erase background works just sometimes

What might be the reason that Erase background works for dynamics like pp ff etc but not for crescendo lines?
I activated it both in the low panel…

Cresc/dim hairpins don’t erase barlines - to the best of my knowledge this is just standard engraving practice, as lines crossing other lines is still quite legible but text crossing lines is not. Additionally, hairpins crossing barlines is a very frequent occurrence and it’s likely that small gaps in barlines around hairpins could quickly become more visually confusing than letting them cross.