Why was Bartholomew Diaz important to Portugal?

First european to reach the indian ocean from the atlantic. He sailed arpund the southmost tip of africa

He became the first European mariner to travel round the southern tip of Africa, this opened a way for sea routes from Europe to Asia.

His breakthrough opened the door to increased trade with India and other Asian powers.

It doesn't sound like much but this was a big deal considering at this time no one knew the southern tip of Africa existed.