Comment by phire

They are suggesting bypassing the RP2350's internal switching regulator (which only needs an external coil and some caps) and replacing it with an external linear regulator (which is actually supported by the datasheet)

Switching regulators have much lower power draw (which is important when running off batteries) and generate less heat, which sometimes leads to a more compact footprint (though I'm not sure the RP2350's core uses enough power for that benefit to kick in)

The power/heat savings don't really matter for this usecase, and linear regulators have the advantage of producing more stable power, though you are hardwiring it to 1.2v (a small overvolt) rather than using the ability of the internal regulator to adjust its voltage on the fly (adjustable from 0.55c to 3.30v)