Originally Posted by
WolfiesPapa
I write credit scoring algorithms for a living, so might be able to answer this: one of the best indicators for a credit ratings is past behaviour, i.e. how do / did you behave with credit granted to you (=credit card, mortgage etc.) With these challenger banks as they typically only issue debit cards, no credit cards, you would lose that part of your credit history over time and hence might be downgraded.
That’s just one of many factors though, so wouldn’t overrate the importance.