Because units less than a litre are so common. 2ml of syrup, 4dl of flour, 12cl of wine, 0.5l of beer, etc. But things you measure by mass rarely go below 1 gram (in day-to-day life at home). Candy bar is 50g, a packet of cheese is 200g, a chunk of meat is a kilogram. Besides, most people just call it "a kilo" so the common units in the spoken language are "a kilo" when talking about mass and "a litre" when talking about volume

9.76N to 9.83N depending where you are, if you want to be super pedantic.

https://www.newscientist.com/article/1987831-gravity-map-reveals-earths-extremes/

"Mount Nevado Huascarán in Peru has the lowest gravitational acceleration, at 9.7639 m/s2, while the highest is at the surface of the Arctic Ocean, at 9.8337 m/s2."