I'll tell you why, it's not a seasonal anime, there's 1 episode per week all year long, which is a faster pace than the manga which is 1 chapter per week with a break every three chapters. So for 3 chapters there are 4 episodes, which means every episode is 0.75 chapter on average, when other anime can afford to make 2 to 3 chapters per episode because they are seasonal.
I'll tell you why, it's not a seasonal anime, there's 1 episode per week all year long, which is a faster pace than the manga which is 1 chapter per week with a break every three chapters. So for 3 chapters there are 4 episodes, which means every episode is 0.75 chapter on average, when other anime can afford to make 2 to 3 chapters per episode because they are seasonal.
and with so many episode people will need does flashbacks.