I disagree. National polls project the popular vote. State polls project the Electoral vote.
Al Gore won the popular vote by about a half a million but he lost the Electoral College and the presidency by 537 votes in Florida.
Its not so much how many votes a candidate gets as it is where they get those votes. Donald Trump might win Georgia by a million votes, he still gets 16 electors. Clinton might win California by 1 vote, she gets all 55 electors.
Taking an average of several most recent state polls is a good way to get a realistic sense of the state the race in that state. I never trust any one poll, state or national.
When in the last 100 years has the the election had more than 2% difference in the national lead and the electoral college not going to the winner (hint: never). And even though EV are what matters, the direction of states WILL MIRROR national polls. It is not possible for Trump to be up 5 in florida and down 10% nationally (bloomberg, cbs, etc) when we lost Florida by 1-3% in the last two elections and only lost nationally by 4% or win Nevada where we lost the last 2 elections.