I've used crisis helplines on multiple occasions and found they're really best for people experiencing acute rather than chronic suicidality. Turns out the "crisis" in the name isn't just for show that way.
For the chronically suicidal, they are a high-risk activity that can lead to unnecessary hospitalization, and their operators are often ill-equipped for anything other than talking people down from an immediate emotional breakpoint. Taking precautions, like making sure you can immediately leave the area and your phone behind if you suspect they have notified emergency services to come get you, is important.
Overall, they're a bandage, a mark of a state looking for a way to provide mental health services that's cheaper than the cost of not doing so - in this case, cleaning up bodies. Like any bandage, they can be useful in the right circumstances, but they're far from perfect.