If I understand correctly, Pandas original scope was indexed in-memory data frames for use in high frequency trading, making use of the numpy library under the hood. At the time it was written you had JPMC's Athena, GS's platform, and several HFT internal systems (C++ my friends in that space have mentioned). Pandas just is so darn useful! I've been using it since maybe version 0.10, even got to contribute a tiny bit for the sas7bdat handling.
indeed it's both: it was created for financial analytics, and it provides R dataframe features to python. thanks for.making me detour into the history of it.