Ringing Ceders

I have been hearing people talk about using secured debt consolidation mortgages to pay for things lately. I know people who have used them for home improvements, trips, paying off credit card debt, and new cars. Are these types of loans really worth it? How low are the interest rates? I would worry about all the interest and probably not consider this unless it was an emergency and I had no other options, but I know I hate to owe money on anything, so I am not like most people in that. I try to pay off my debts ahead of time.