I read that Barcelona will not play in Camp Nou because it is not ready yet and they will break La Liga record when facing Valencia this Sunday in Johan Cruyff. By La Liga record, they mean the stadium with the lowest capacity ever!
I don't know why they picked this stadium and couldn't find another bigger one because the number of tickets will be very limited so less revenue for them at the time they are desperate for money..
Barcelona seems to want to provide the best for their fans by renovating their stadium, as it's a source of pride for the club. This is the reason they're undertaking extensive renovations to improve the stadium's facilities to make it one of the most advanced in the world. This is understandable.
While the John Cruyff Stadium may have limited capacity, it's home to the Barcelona women's team and Barcelona B. This is likely why it's Barcelona's current choice. However rumors are circulating that Camp Nou will soon be ready for use, and Barcelona will play their home games there.