Barcelona will need to keep up this performance against smaller teams until the next El Clasico in the league. If they do this and defeat Real Madrid in Camp Nou then I think they can really be the champions after a three-season break.
Barcelona are more convincing this season than last season, but we are still the best in El Clasico. Real Madrid won the first volume of El Clasico, but that doesn't guarantee we can win in the second volume later at Camp Nou.
Comparing Barcelona's performance with the previous season, it is easy to see that their performance has improved. If they get stronger gradually. Because this season Xavi has spent a lot of money building his squad. And added several talented players to the team. Hence their performance has improved. But this performance was not enough to win the title. Barcelona need to play better if they want to win the title. And of course, 3 points must be secured against relatively weaker teams in every match. If Barcelona does not play consistently well, Real Madrid will be the champions this season.
For me, the El Clasico match cannot be used as a benchmark for Barcelona or Real Madrid to win the title, because even if they win or lose the El Clasico match, the reality is that Real Madrid and Barcelona will at least get defeats and draws when playing against other teams. It doesn't matter that Real Madrid and Barcelona lose to weaker teams, because sometimes it happens too.
So yes, in this case Real Madrid and Barcelona will continue to compete for the La Liga title, but whether they can win the title or not depends on their consistency and not on El Clasico matches.
Because basically the El Clasico match is just a match with the title of big match and not a decisive match, so because the match is a big match, of course they have very high prestige.
But regarding Barcelona this season it has undergone significant changes even though they are only promising in La Liga, while for competition in Europe the reality is that Barcelona is still not as good as in La Liga.