It's doubly bad because 1) you lose access to the 50,000. It goes from a liquid investment (cash in the bank) to an illiquid investment (your house). 2) because you can earn a higher return on your money by leaving it in an investment account so you lose the income difference. If you can get 6% on that 50,000 then you're giving up the 1% difference between what you can earn (6%) and what you have to pay (5%).
Yes, you can rebuild the 50k, but that first 50k is still no longer a liquid investment. Also, even if your mortgage payment (not including taxes and insurance) was $2,000 a month it would take you more than 2 years to rebuild it assuming that you made savings deposits equal to your mortgage payment. And if you're forced to do that then you're monthly budget is no better off for that period of time and you're mortgage would've been paid off in the next month anyways. So, you would've saved only 1 month's mortgage payment while forgoing all interest income on the initial $50,000 (which would've made up for most of that last payment).
Doesn't sound like a good financial decision to me.
Sorry to keep rambling about this, but advice to ignore credit at all costs is NOT good advice for most people. It's also not even the point of hookemdown's request for advice, which is answered simply by getting at least one credit card, using it (without increasing monthly spending), and paying off the balance each month.