I would assume that a printer (or the printer driver) does more than just stupidly repeating dots until meets the pixel dimension, but uses the printer’s capability of applying droplets of various sizes.
The reason why it is better to enter the native printer resolution in Lightroom’s printing module is simply that the scaling algorithms of e.g. Lightroom (or QImage, which I use) are more intelligent than the rather simple ones in the drivers.
BTW, the “ppi” term is actually correct in the printer dialogs - it describes how many of the image’s pixels will ultimately land on one inch of paper. They get there by the printer intelligently spraying dots (droplets) of various sizes and colors for each pixel. That’s why the dpi capability of a printer is much higher than e.g. the native printer resolution, be it 360 for Epson or 300 for Canon. At least that’s my understanding.