I also don't understand why Real Madrid and Bayern Munich face rivals from their league of course this is the same as seeing them compete in their own league not like in UCL even though it could be reversed like Bayern with Madrid and Atletico Madrid with Leverkusen then it will make the competition feel more curious I also feel that the four clubs seem equal which makes it difficult for most people to predict who will win even their meetings in their own league are already difficult to predict, but in UCL I think they will play harder than usual because everyone wants to continue to qualify for the next round.
That is what this stage is all about, the ban on same nations thing gets lifted here, so they are facing teams that are from another country, which does benefit the teams in a way that makes it good for fairness.
If we kept seeing teams avoid same nation until the finals, things could have been easier for better leagues, and very tough for smaller leagues, which is why there is a level to this, they just want to make sure that we are dealing with teams that will face whoever, that way if two great teams from the same league is in then they can face each other and knock one off, instead of just having two of them bulldoze over everyone else until the finals. Last sixteen is where they let that happen and that's why we are seeing those two matchups.