Once upon a time, it was desirable to record hot because a strong signal could drown out the intrinsic noise of magnetic tape. It's a different world today, but old rules of thumb persist, even when they no longer apply.
Some justify the concept by saying you have to "use all the bits". Truth is, modern signal-to-noise ratios are so ridiculously high that it almost doesn't matter what level you record at. Within reason, of course. Noise isn't completely gone. Digital recording brings its own kind of noise, and all the analog devices we record still add their own noise. But you could still record everything at -30 dBFS and all would be fine.
I would never, ever set 0 dB as my target. Not for recording, not for mastering. In the weird math of digital audio, 0 + 0 can equal 6!