This looks like grafana, right? Why would I use this instead of grafana?
To make it more concrete -- coworkers tell me Grafana doesn't work so well with Apache Druid, while Superset supports it quite well.
Grafana I sense is culturally focused on observability visualization (aka needs of full stack devs). Culture is very hard to change!
superset is the flip side of grafana; not good for up-to-second updates, but good for complex queries. Also, non-time series stuff. Ex: Which customer groups bought which products for all time? <— that type of BI stuff.
As such, closer to an open source replacement for PowerBI.