Cold rolled steel has a number of advantages that make it an attractive option for many metal-working projects -- most notably, it is considered easier to work with. However, there are several disadvantages to cold rolled steel. The determining factor should be the type of project you're undertaking.
One major disadvantage of cold rolled steel is price. Since clean ingots must be used, cold rolled steel can cost twice as much as hot rolled steel.
Work hardening, or the hardening of metal through a process known as "plastic deformation," is sometimes desirable. However, cold rolled steel sheets have a tendency to work-harden during the rolling process, making secondary machining and shaping of the metal very difficult. Work-hardened metals can damage equipment.
Buckling is a major concern with any project that uses steel as a beam or a brace designed to bear weight. Any design will have to account for "column" and "lateral" buckling of unbraced beams. But cold rolled steel can also cause "local" buckling at stresses below the yield point because it is usually thin in relation to its width.