As for why, my bet is to prevent "counterfeit" (as Lego would call them) lego parts being shipped by vendors. They target low-income countries, as it is profitable there to import China-made bricks and sell them on Bricklink to make a living.
As a background, there are plenty of chinese lego alternatives, operating mostly legally in the west as the lego patent has expired long ago. Brands such as Mouldking, Cobi, Bluebrixx, CaDa, etc. are available here in Germany even in retail stores and online, and it is perfectly legal to sell "alternative" bricks. Cobi itself manufactures all of its part in the EU (mostly Poland) and creates original designs (mostly War-themed models such as tanks, fighting jets etc. as Lego does not do those).
As a background, there are plenty of chinese lego alternatives, operating mostly legally in the west as the lego patent has expired long ago. Brands such as Mouldking, Cobi, Bluebrixx, CaDa, etc. are available here in Germany even in retail stores and online, and it is perfectly legal to sell "alternative" bricks. Cobi itself manufactures all of its part in the EU (mostly Poland) and creates original designs (mostly War-themed models such as tanks, fighting jets etc. as Lego does not do those).