I studied gemology for years and I’m certified in diamonds by GIA and I agree 100% that they are exactly the same structurally so why spend the extra money when you don’t have to, 

HOWEVER 

Knowing everything that natural diamond goes through on its way to becoming set in jewelry is what sets is value so high. Every natural gem is truly a miracle, like a shooting star.

It’s also a beautiful metaphor for life and love. Anyway that’s my two cents.