When you buy a condo, you are (usually) only responsible for covering your interior unit. The building, the common areas, the roof, etc. are all jointly owned with other condo owners in your building, which would (usually) be covered by your homeowners association (HOA).
When you buy a home (or a townhome, in some cases), you need coverage for the entire dwelling, not just the interior unit. You are responsible for rebuilding costs of the entire home, as well as other structures such as fences, sheds, and carports. The coverage is typically going to be higher on a homeowners insurance policy.
What's typically covered?
For both condos (HO-6) and homes (HO-3):
Flooring (carpets, hardwood, etc.)
For homes (HO-3) only:
These may vary depending on your policy.