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.
Well, everything is drawn randomly. So it is not surprising to see two teams from the same league face off in the round of 16. And this also happens quite often. But the teams from the Premier League seemed quite lucky because there were 3 teams that managed to qualify for the round of 16 and fortunately none of the teams met each other in the round of 16. Arsenal will face PSV, Liverpool will face PSG and Aston Villa will face Club Brugge. And it would be extraordinary if all three could advance to the next round. But I think one of them will fail in this round. Whether it's Aston Villa or Arsenal. Meanwhile, Liverpool, I think they will win in the round of 16. Even though the opponent they faced was a strong opponent, namely PSG. But I still believe Liverpool can win.