Do signup bonuses hurt or help you guys? It has always hurt me.

Two or three different times at different casinos I won a fair amount of money and wanted to cash out but most do not allow you to cash out minus the bonus. So basically they have always only hurt me rather than me benefit from them.
What are some of your experiences?
I wouldn't say help or hurt. They're mainly designed to get you playing there & they hope you enjoy their site & play regularly. I doubt anybody wins big with their sign up bonus. It's just to attract you to the site & get more money out of you in the long run