JB Dyas likes to quote a study that claimed that students who watched their hands while learning scales learned them more quickly than students who did not. It's worth noting that JB plays exclusively fretted BG - very well, I might add - and I don't know if he teaches URB. In his quote, he's also not talking about intonation but learning scales.
I've taught alongside JB for 20 years. He doesn't play upright at all, although he admires the instrument greatly. When he talks about watching the hands, he's talking about (as you say) "pattern mapping" the relationship of the notes in the scale to the layout on a fretted BG in 4ths tuning. FWIW, I find this concept very useful on the DB as a way to visualize how certain lines might lay out in a basic sense, but as you and I know all too well the DB is a different beast, and requires a whole different level of precision in the technique/intonation department to bright those ideas to musical fruition.