Your are partially right. Because you did not give the full detail of the 6% p.a. rate. whether it's a effective rate or otherwise.  Another reason is that there is a possibility to accumulate credit card debts again in the future after the full settlement.    
Why wrong ?? Mind to explain it in public ?? Why need to be so secretive ??
I reckon you are talking about 6% p.a. flat right ? Well....even if it is 6% p.a.flat, the effective rate is still below 10%. Thus, using a 6% p.a flat personal loan to settle a 1.5% p.m monthly rest credit card loan is not  a wrong way to reduce the monthly interest cost.