Good point. It's a disadvantage too. Esp when the opponent is a tactical team like Atletico or Juve capable of being flexible and playing in different way or counterattacking.
Playing at home first AND taking the lead is a pretty big advantage. In second leg, the team with the lead can set up in whatever way they want. The other team needing to score is predictable and can play in only one way. And as the match goes on, pressure builds up more and team trailing becomes even more susceptible to choking while at the same time becoming even more predictable.
The myth of playing at home second being better is just that - a myth.