When Conservative Republicans, both regular people and more famous ones state that Joe Biden is better for the country than Donald Trump, it certainly allows other Conservative Republicans to think about their devotion to Trump and whether he actually represents them, or is a snake oil salesman charlatan telling them what they want to hear. It shakes some loose, not change en masse. The big questions are the impact of Russian disinformation campaigns on the No Trump voters, and how difficult the Republicans make voting, especially in swing states with Republican governors in a balanced population of voters.
Republicans have a lot of tricks. Purging voter rolls, that for example showed 30% of purged voter registrations in a Georgia action were actually eligible; closing polling places, especially in high density population areas; putting broken machines in heavy Democrat districts; hiding boxes of votes; requiring ID checking in a slow process while reducing staffing at polling places to check it; eliminating or reducing early voting (like in Wisconsin). Long lines can occur to even a mile or more long using the 6 feet social distances. 5280 feet says an 880 voter line is a mile long. In cities, lines can go for miles and seeing it CERTAINLY discourages voters.
Republicans cry about ineligible voters voting, which studies show is a tiny number even if true. Yes, there has been some double voting by mail and in person, felons voting, people voting for a sick relative, driver license voting registration that registered ineligible voters that a small number think they can vote in a double error. This ineligible set is somewhat less than 0.1%. Far larger numbers fill out their absentee ballots incorrectly and get disqualified.
This is a good thing getting support from hardcore Republicans, but don't let polling fool you since some Trump supporters lie in polls, won't admit they are Trump voters even to friends and family, and the Not Trump is over 60% of the Biden base as not nearly as secure. But, as one lifelong Republican stated on video, if Biden drops out and the Democrats put up a tomato can, he will vote for the tomato can over Trump.
For me, a Buttigieg volunteer and contributor, he says Biden and that is good enough for me.