The reason people use sailor sakura is mostly due to her self recovery on hit. This makes her very difficult to focus down, so the classical strategy of "kill the healer first" won't work so well unless they can ignite her. Using regular sakura, regardless of star or breakthrough will usually simply see her dead by turn 3, which mostly defeats the point.

That said, you lack a secondary cleanse to make sailor sakura reliable in the face of CC/ignition. So using her would see you beat opponent who have no counter almost all the time yet lose to opponents that have ignition also almost all the time. Of course, there is always the hope that you will grab a secondary cleanse from the opponent with the yagura, but that is unreliable. So overall, it makes sailor weaker than she usually is. Still, due to the fact that she is at least harder to focus down than regular sakura, she should still be better.

i've done all breakthrough.

i've used SB sakura a few times in arena. When i expected i'd match against DP hidan. Only if you see the pattern when you're going to vs same people a few times.

other than that in general sailor is still far better because of her aoe and scaling dmg.

sailor's slug eat gnw sakura slugs alive in 1 or 2 hits.

sometime normal sakura is better than sailor if you face hidan team because she c*e mystery at round 1