Most people speak English, but are uncomfortable / inexperienced in doing so. Everyone in tech speaks English just fine.

For day-to-day, it does make your life much easier. Surprisingly, banks are a pain to deal with, without speaking Portuguese. I learned because my parents in law didn't speak English very well.

Portuguese is a rich language, and Portuguese people are typically familiar with the countries famous writers and poets. That makes it a valuable language to learn.