I agree, its weird to see local leagues having winning series like best of 3 or 5 to advance where in CL its only a win + 2 sets. And CL supposed to be worthier or harder than local leagues. It would also be a win-win for fans, we see these teams playing agains each other only couple of times in a year and thats it. some top teams dont even play against each other for years.
I think is because of tight schedule in european leagues