How does staying informed on certain issues help voters?

It helps them figure out who they should vote for. If you care about education and members of one party are doing nothing about it, then you might want to vote for the other party, even if they are not yours. Otherwise, you might simply vote a straight ticket for your party.

For instance, suppose a Republican is transgender, they are in North Carolina, and it is the 2016 election. They might vote for Donald Trump (R) and also vote for Roy Cooper (D) to get rid of Gov. Pat McCrory (R) who signed the controversial law against transgender people. If they were not informed, they might have voted again for McCrory. And if they were even more informed and realized Cooper's stance on Immigration, then they might consider a 3rd party candidate, though that could increase the chances of McCrory win since that would be a vote spent on a candidate that likely cannot win because that party is too small.