New with warranty they’re going for $2400 at B&H for a 16”

https://www.bhphotovideo.com/c/product/1668190-REG/apple_mk1a3ll_a_16_2_macbook_pro_with.html

So unless you feel your M1 Air is worth only $300, not a great deal.

Save the $100. The difference in “portability” is insignificant, and for $100 LESS you get a better, brighter screen and a bigger trackpad, both of which are more meaningful than 0.2 pounds.