Thanks for pointing this out! In fact, I was pleasantly surprised to find this 16-inch model is very slightly smaller in each dimension than the 2015 15-inch rMBP.
2019 16-inch, per https://www.apple.com/macbook-pro-16/specs/ :
Height: 0.64 inch (1.62 cm), Width: 14.09 inches (35.79 cm), Depth: 9.68 inches (24.59 cm), Weight: 4.3 pounds (2.0 kg)
2015 15-inch, per https://support.apple.com/kb/SP719?locale=en_US :
Height: 0.71 inch (1.8 cm), Width: 14.13 inches (35.89 cm), Depth: 9.73 inches (24.71 cm), Weight: 4.49 pounds (2.04 kg)
