Banks and licensed lenders are two different worlds, even though the same KNF supervises both. A bank has higher requirements, a longer procedure, but a lower RRSO. A lender approves faster, accepts a less-than-perfect profile, but the RRSO climbs.
When a bank
You have a regular employment contract or you've been self-employed for over a year. Your BIK is clean or has minor positive entries. You need 10 000 PLN or more. You can wait two-three days for a decision. Under these conditions, a bank almost always comes out cheaper.
When a KNF-licensed lender
You need the money today, not in three days. The amount is small (up to a few thousand zloty). Your BIK has minor scratches, or no track record at all. You'll pay it back in 30–60 days, not in 12 months. Vivus or Wandoo will give you a first loan at 0% RRSO if you pay on time — that is a one-off promo, repeats are pricey.
When neither
You don't know how you'll pay it back. You're taking out a loan to pay off an earlier loan („rolling"). Your monthly payments already eat more than 50% of your net income. Those are signs that the problem is not a missing loan — it's the structure of your spending or income, and a new loan will deepen it.
How to check a lender is legitimate
Look it up in the public KNF register at rejestr.knf.gov.pl. Every lender operating in Poland has to be listed there. If they aren't — don't borrow. On top of the register, the Polish anti-usury act of 18 December 2022 caps the non-interest costs that can be charged. Both rules apply at the same time.