"Existential dread is a key motivator for asteroid discoveries, and planetary defense experts hope that, by surveying nearby space rocks, they will identify a threat with enough time for us to protect ourselves."
Exactly (and I mean with all the engineering, celestial mechanics, kinetic energy dynamics, and other specifications) do we "protect ourselves"? At this time, to use some modern vernacular, we got nothin'. Ideas, proposals, silly movies, and everything else in our stop-that-big-rock inventory are meaningless and will remain as such for the next half-century at the very minimum. That means watching these beasts hurtle by is academic fun masquerading for funding purposes as some kind of early warning system, which it most certainly isn't, primarily because 1) we can't stop or redirect the incoming doom stones and 2) we don't see the city block-sized variety most likely to make a hit until they're almost on us or have just slid by: "Boy, that was a close call, heh-heh-heh," for the latter, and "Whelp, there's OUR extinction event in 18 hours" for the former.
"Planetary defense experts," indeed.