I've never understood the appeal of using a product like Affirm, especially if you already have a credit card. Credit cards already give you a 30-day grace period before purchases start accruing interest. Using Affirm to extend that to 42 days seems inconsequential. It seems like their target customer are people bad with credit, which would make them predatory.
I had poor credit from student loans and Affirm was very generous to me when other banks weren't. Affirm helped lay the foundations to rebuilding my credit. They've been good for at least my case
Does Affirm report paid-off loans to credit agencies?