It sounds like the big piece of work is adding the many European exchanges. They’re building it in such a way that makes it easier to add more exchanges in future. e.g. Australian and Canadian that have been announced so far. (I’m sure there’s more on the roadmap, just not announced!)
Once this piece is complete they will have recruited a larger team to add Crypto, their list of features and more ISA types (European versions then JISA’s, LISA’s).
Launch quickly then improve the app iteratively seems to have worked well in the UK.