While the media likes to pretend that crowd size doesn’t matter and this is just a weird Trump obsession (OK, clearly, Trump is way too obsessed with it— remember all Sean Spicer’s strange lying about inauguration crowd size from the podium in the first days of the Trump administration in 2017?), crowd size is important in politics. Big crowds tend to equal big media attention. Big media attention often ends up meaning big election results. Just ask Trump or Obama.
Beto has some advantages he can work over and above other candidates already in the race if he chooses to run for President. And if he does, whether or not he’s anyone’s first choice candidate, he might end up getting a lot of progressive love just because he obviously bothers Trump— maybe even scares him.