I've never used a printer with auto bed leveling, but my understanding is that most or all of them don't actually level anything, but rather compensate for the unlevel bed in firmware by transforming the coordinates. It seems to me this would necessarily introduce aliasing artifacts in all your prints by making it so that line widths are no longer a whole number of microsteps - I immediately observed such an effect on top/bottom skin when I tried to use steps-per-mm tweaking in firmware to compensate for a dimensional error rather than fixing the mechanical source of the error, and concluded that it was a dead-end approach.
If the auto-leveling firmware only makes adjustments with the Z motor as it moves, rather than transforming all three coordinates, it seems like that would be mostly or entirely mitigated, but with slight errors in dimensional accuracy dependent on how tilted the bed actually is.
Do any of the printers with (or add-on kits for) auto bed leveling actually level the bed mechanically, with servos attached to the adjustment knobs? Why isn't an approach like that more common?