There is maybe 1 in 50 jobs that I'd actually want, so I imagine bulk applying to would guarantee I land something awful.

Not everyone has the luxury of choice though when it comes to employment.

Unless you’re the employer being deluged

Downside is when you have to make slight changes each time to better emphasize some aspect of your experience, depending on the job applied for. Recruiting agencies often do this to sex up their candidates chance of winning the job lottery.