I don't think it's wrong, especially if you have a life insurance policy that becomes void in the event of a suicide. In that case, if you can successfully CTB and make it look like an accident, then the policy would still be in effect. Aside from that, it could also be good if you have loved ones who would be devastated if they knew you committed suicide, but would be able to handle it a little better if they thought your death was accidental.
I think there are a lot of good reasons to stage it as an accident, but the tricky part is actually being able to pull it off. I would love to be able to do it myself, but I can't see it working very well because I would probably die painfully, if I tried to make it look like an accident and the more effective methods I want to use would make it clear that it was intentional.