Yes, they very well might make a real difference.
Most states are winner-take-all come this November, but Maine and Nebraska are different. Maine and Nebraska give two electoral votes to the winner of their state and one electoral vote to the winner of each congressional district.
This opens the door for Republicans in Maine and Democrats in Nebraska to chip away at least one electoral vote from the opposite party. That means that both of the presidential nominees are spending time in these states in case things get much closer than most think possible.
Most electoral map scenarios favor Hillary Clinton. Donald Trump is deluded enough to think that several battleground states will fall his way in order to hit the 270 magic number.
The rub is that there are some potential scenarios of electoral votes ending in a 269-269 tie and so that then means that a single congressional district in Maine or Nebraska could make the difference.
Hence the campaign time might be well spent in Maine or Nebraska.
(And now you know the rest of the story.)