Interesting. I was just curious but, without doing a search, I'd think Brazil has a larger population by far then does Portugal so, it'd be logical to do it in the Brazilian dialect. I keep hearing the same about Mexican Spanish and Castilian Spanish but never from a native speaker of one who has been to the other. As far as my own experience with British English, it was mainly from pilots (whether that matters or not - it's just who I was in contact with as a NATO weather forecaster/briefer) and I had no trouble understanding them other then some jokes that fell flat to my ears. The same was true when I watched "The Benny Hill Show" on TV.
I speak just one language myself so I have another general question. When a game like Divinity is done in another language, are the voice actors changed to that language or is it just the text? If the prior, that would explain the delay. It's one thing to read and understand a second language and another to translate. They would need both a rock solid translation and good Portuguese speaking voice actors which may not be easy.