If you've ever faced Haruka (and the whole 68 team) in Scrimmage, you can see how terrifying she can be when upgraded. The mistake a lot of newcomers make is leaving her at 1-star. No unit is good at 1-star, they only start to shine at 3-stars and above, and some really open up and become great at 5-star with their unique weapon upgraded at least once.
Blue archive is one of those games where some initially 1-star units become real winners once you get them to 3-stars. Arguably the best tank (Tsubaki) and healer (Serina) for most situations start at 2 and 1 stars respectively.
On the other hand, there are several pay to win girls, including limited only pay to win girls that you NEED to compete at higher difficulties and / or PVP, so there is that.