I always thought burqa referred to the central Asian / Afghani version of the Niqab, meaning a long top of the head to toes dress that does not break at the shoulders - ie no scarf and then abaya but a dress that ties at the top of the head and flows loose all the way to the toes.

Indeed - the traditional Palestinian type of Muslim scarf dress is also the same in the dress you can see on all depictions of Orthodox Christian churches. This was not a Muslim dress but a regional dress of Palestine that then became an identifying appearance for Muslims when Islam reached the area.

Same for niqab, women wore it while living in the desert to protect their breathing pathways from sand and wind. Remember they lived under cloth tent, not in house. Men also wore head gear that could wrap around the face as needed.