However, that's often not the point. If you are progressive (conservative) there is a strong incentive to challenge incumbents on your own side because any impact you have on the ideas discussed is likely to work in your favor; and indeed it's possible the incumbent agrees with you on those issues but just wants political cover to acquiesce. So I'm not really troubled if Cuomo happens to discover a more progressive streak or makes some concessions even though he's going to pulverize her come polling day.
I think it would be accurate to say that Nixon has run an unusually strong campaign and done an unusually good job of calling attention to real issues, even knowing she has no chance of winning and isn't a serious candidate by that standard.
[Note: I am not a resident of NY State and can't legally vote in the state I live in.]