A boshiyyah is normally not as opaque and covering as a traditional niqab; they can also be worn to supplement a half-style Niqab or if the wearer desires extra modesty around non-related (non-mahram) men.
A boshiyyah is usually not as opaque or concealing as a typical niqab, and it can be used to enhance a half-niqab look or provide extra modesty when interacting with unrelated men.