What You Were Thinking: The debt is costing 19%, the retirement account is making 4%, so by swapping the retirement for the debt you will be pocketing the difference.
Your Mistake: Withdrawing funds is easy, but it's very hard to pay back those retirement funds. With the right mindset, borrowing from your retirement account can be a viable option, but even the most disciplined planners have a tough time placing money aside to rebuild these accounts. When the debt gets paid off, the urgency to pay it back usually goes away. It will be very tempting to continue at the same pace, which means you could go back into debt again - but this time five years of savings will have been wiped out too.
If you are going to do it, you have to live like you still have a debt to pay - to your retirement fund. Keep that need-to-pay mentality you had with your credit cards, and create a plan to pay yourself back. (Learn more in 8 Reasons To Never Borrow From Your 401(k).)