It depends on your scores signing on for them. If you don't have good credit, they can be a nightmare long term. I do think that they are great options for people who are just starting off with credit though. My first card was with a department store and was a very low allowance ($300 to start) but I quickly got that up to $1,500 the first year.
Some are just for building your score up in a more controlled setting. My parents always struggled with managing their credit so after they filed bankruptcy and waited a few years, my mom was able to get a few credit lines at stores and has been able to maintain them just fine.