Barcelona will act as hosts in the second leg, this is one of the factors why Barcelona deserves to be favored over Napoli. It's true that Barcelona as a whole posted better statistics, Napoli experienced setbacks and had to change coaches twice this season. Even though Xavi plans to stop at the end of the season, he is determined to take Barcelona further in the Champions League this season. Apart from that, in their last match Napoli drew, while Barcelona managed to win.
The match between Barcelona versus Napoli is difficult to predict, because Barcelona not too dominant over Napoli. However, Barcelona has more complete attributes than Napoli, such as a more even squad depth and a better reputation. It could be that Napoli managed to get rid of Barcelona, but on paper Barcelona is the right favorite. Everything will be proven in the second leg, betting on their victory seems very risky.
The problem still lies in the performance of both clubs which is still very difficult to guess until now.
Honestly, by looking at their first leg matches and some of their performances in domestic competitions, I am still quite doubtful about who will eventually qualify for the quarter-finals because their performances are still unpredictable.
At the moment the situation is still fifty-fifty although indeed playing at the Camp Nou is not wrong to make them a favorite in this match but with Barcelona's current performance it also cannot be a guarantee actually.
Currently, Barcelona and Napoli's problems are still the same where the problem is the poor finishing, only Napoli's advantage at this time is that Barcelona will not be strengthened by some of their productive midfielders because De Jong and Pedri are currently following Gavi for a slightly longer treatment so this can be used as a good opportunity for Napoli.