I don't think the teams will have much advantage in home matches. Barcelona and Manchester United are both strong teams now. And so it is unlikely that the home team will have an advantage. Barcelona doesn't get any extra facilities at Camp Nou. However, Manchester United will be slightly ahead in the next match. Because in the first leg match United several important players could not be with the squad due to injury. Manchester United team will be stronger if they are with the squad in the second leg. And it will be more difficult for Barcelona to perform well in the second leg.
Playing at home will make Manchester United a favourite, of course there's nothing wrong with that.
Barcelona have tried to do well at home even though they were forced into a draw by Manchester United. Xavi had tried everything to change the final score, but it didn't work even though Barcelona were so close to winning at home.
They will determine who advances to the next round in the second leg on February 24, and it will be the most eagerly awaited match. Barcelona are missing several players, it's a loss while Manchester United are expected to maximize their home advantage to win. But after last season's failure, I think Barcelona have been better in terms of their performance this season in the Europa League. So the match will be interesting to wait for.