Seems to be part of the black Friday deals they've unlocked early. Usual price is $265, but $165 seems to be a discount price that pops up regularly. I had this tagged on price hipster since my old Fitbit has hit 4 years and going strong but was feeling like getting something with GPS on it.
Includes 6 months Fitbit Premium.
Maybe you can price beat at Office Works if it's worth your while. Also can be had at JB for $169 for the same range of colours - https://www.jbhifi.com.au/products/fitbit-charge-5-black-gra…
Edit: a word.
Currently $164 in amazon, White and Blue