Perhaps it's not, but it is a bit more compact and even more so in my native language, Swedish. The names of months are longer: "September", which is the same w

Perhaps it's not, but it is a bit more compact and even more so in my native language, Swedish. The names of months are longer: "September", which is the same word in Swedish has four syllables while the word for week ("vecka") has two. And sometimes you really want to speak about the entire week without naming a day ("we'll have the first boards week 40, smoke-test and bring-up during week 41, and then start proper development by week 42"), since it's times in the future and you don't want to be too specific but still align work tasks with weeks. Also (re: a sibling comment) Google Calendar shows week numbers, or can be configured to. For quickly finding out the week number, there's always https://vecka.nu https://vecka.nu. :)