Possibly there's some novelty factor to riding the new trains. My 70-something year old aunt, visiting from another continent, wanted to ride the new trains (and they weren't even fully converted yet, it was day 2 of the soft launch and only a couple trains had been switched over so I had to check the train sightings on Discord). Obviously they're not all that unique outside the US but it's exciting to see them here.

But weekend service is now twice as frequent (now every 30 minutes) which is a game changer, so it's not a surprise that those numbers in particular have shot up since they were pretty weak to begin with.