Right, but that just plays up the "personal opinion" part of the answer (as B-Dubs also notes). If you're like, I think we should keep the death penalty, but if SCOTUS got rid of it that would also be fine, then you are even more directly acknowledging that you have an opinion but you don't consider it a real policy proposal. If you thought it was a policy proposal you supported obviously you'd want SCOTUS to agree with you!
So, I mean, that's fine, Hillary is certainly not the first Democrat to use "well, just my personal opinion" to dodge dealing with a question where the activist left and the Democrat/moderate base differ, but the weird thing to me is that I'm not clear why Hillary feels like it's safer ground to say she kind of supports the death penalty when most Democrats now oppose it.
It might just be left over from when you had to be tough on crime, or maybe she really is just offering a partially considered personal feeling. Except that, as a robot, I don't expect her to do that. The last thing I want from Hillary Clinton is an accurate description of what she personally believes and how it differs from the Democratic Party!