Tell me you either don't love in the US, or don't understand what a credit score is, without telling me...
Every time you open a credit card, you get a "hard credit check". You get one(?) freebie a year, then it starts significantly dropping your credit score. Having a larger amount of unused credit available to you will slightly increase your score, but having too many less of credit (e.g. >5) will significantly harm it.
All that said, credit scores are a scam, but do affect your ability to get a car or home loan, or rent a place to live.
Hard pass on their privacy policy. They have to collect lots of identifying data to do financial transactions in the US, and they don't currently sell that data, but:
They're a startup that just had a huge Series A in 2021. If they're at all successful they'll almost certainly get purchased by a mega bank that primarily wants all that sweet sweet private data that's been getting collected but not shared all along.