Hey sorry for the late reply. I applied at a time when I was unhappy with my job and was unsure of my prospects. During the time I applied I was out doing interviews as well. I got a job at a company I love and am really excited about it. That excitement has more to do with why I declined to go to grad school in the end.
I'm not the OP, but I think it's not that uncommon for people to apply for positions/opportunities that they're either ambivalent about, or outright have no intention of accepting. I know I've done it before.
Some feel this helps them to stay "well practiced" at going through recruitment/interviewing, gives them a good reason to keep their résumé up to date, expands their professional network, gives the potential confidence-boost of being offered a position then declining it, and so forth.