Well it might also be about shoring up some down ballot races for the House...I mean they have spent the past month circling the battleground states I don't think 1 day is going to make a difference here or there. (plus they have a town hall tomorrow on CNN) Early voting in the battlegrounds is probably making them feel pretty solid. I mean a million+ early voters in Michigan, majority women, is a very good start.
And from what little I have been able to see as I avoid anxiety inducing stuff as much as possible, that seems to also be the case in other states as well.
Totally a guess by me, and I do not even pretend to be an expert (and I very rarely stay at Holiday Inns anymore) but I would guess internal polling plus the early voting in Michigan/Pennsylvania/North Carolina/Georgia (especially
where the votes are coming in from) has them looking at where they can goose some Dem turnout elsewhere and force the GOP to have to defend and waste their meager resources. They see Trump in California and his upcoming Madison Square Garden rally (does he have the balls to stiff MSG? We know Arnold Palmer did

) trying to save The House so Mike Johnson will be in power when January 6th happens and the Harris Campaign is going to try and offset that. Plus, it could be very helpful for Colin Allred in his close race with Cruz. Walz is still running around like a crazy man so her taking one day in Texas won't hold her back all that much and if it gives boost to the Dems running in Texas it could be the difference.