The sailing around Africa was done by countries like Portugal, the Netherlands and England. They, unlike the Mediteranean countries, could not profit from the luxury trade which went through the ottoman empire. That is why they took a shot, and found out there were a lot more riches to be found in the east than what did come through the Silk route/Constantinople hub. Like cheap slaves, abundant new spices and other luxury products.

It enabled the Europeans to control the trade entirely instead of being dependend on all the links in between.