I worked as a staff nurse while I was a CNS, in two different hospitals. I got no extra pay for my extra education level, nor anything else extra. I agree, that one is held to higher expectations if he/she is an advanced practice nurse than if not. If you should know something, since you're a CNS, it will be expected that you know it, even if it isn't in your role in the job you're doing.
In my state, an APN license isn't required to practice as a CNS, only to prescribe. In fact, when I applied for prescriptive authority, I was told there is no such thing as a CNS license. Then, surprisingly, after I got prescriptive authority, I got a CNS license in the mail. I don't think the people I talked to knew all the ins and outs.
I think there's lots of grey in this and you should be careful.
As for the difficulty finding CNS schools...I think NP schools are more preferred these days and maybe CNS education is being phased out. ??
When I worked in a general hospital, every floor had an CNS, including the ED. My CNS job there was phased out as "not needed."