Actually, Jeff, if your invisible yellow dragon was giving you hope, and telling you to do good things, all the more power to you. I'd probably think you were hallucinating, unless I saw some evidence of invisible yellow dragons too... but whatever. I wouldn't want you locked up unless your invisible yellow dragon was telling you to be a bad person, to hurt people, etc.
Now, as nice as that seems - and it surely is sincere - do we really want people to be comforted by delusion? I would rather be surrounded by honest non-deluded people, than by those smiling and happy all the time, if I knew that the smiles and happiness was all from mental attachment to delusions.
The last portion of your statement touches on one of the major problems I see with religious delusionalism - it causes massive harm, although it is insidious in nature. Those caught up in delusion in their productive mental years will harm others by failing to use the brain and sometimes genius housed therein to benefit mankind. If Einstein and other great minds had been busy 'praying and fasting' instead of studious inspection of the universe and it's laws, we would be less advanced than we are. It is impossible to state how far behind we are as a species due to the delusions of millions of fine brains who never contributed to the advancement they could have.
Jeff