Had Ellison won, how much real difference would it have made? Perez is more representative of the party's core. At least with Perez, what you see is what you get. Ellison might have attracted more progressives and young voters into the fold, but then what? Sucker them, again, into campaigning for the next lesser of two evil Demo corporate whore in 2020? (Hello! Remember Bernie Sanders?) Give them lessons on how to co-opt the resistance movement as a good Democrat should and always does? The cycle repeats itself, regardless if it's Perez or Ellison.
At least with Perez, some in the resistance won't by lured by the Democrats yet again. Some may actually seek alternatives, now. Some may actually start thinking outside the Democrat-Republican box. Even those that choose to side with the Democrats may be a bit wiser and willing to ask hard questions of the party's elite. This isn't necessarily a bad thing.