A) If you're "really poor", your credit rating is likely to be poor to catastrophic already.
B) It's still a larger loss to loose large fractions of your income, and all of your wealth, and your credit-rating, instead of losing only your credit-rating.
C) If you're "really poor", then there's very few situations where getting credit will help you, it will help short-term, but at a cost of additional pain longer term. The exception is if the short-term cost is for something that gives you additional income longer-term. (say buying a used car, to be able to commute to a new job you got)