My memory is fuzzy on this (and I may have misunderstood it the first time), but at least in some states when you register to run for President you provide a list of your electors if you win, so basically a vote for you is a vote for those people to appear at the electoral college vote.
So basically I think Miller is saying Trump’s electors are going to meet and cast their votes in favor of Trump, which is basically their entire job. Just so happens it means absolutely nothing if you don’t win the statewide vote.