How so? The only possible issue I can see about that solution is that you can't see your own car in the side mirrors and thus judging relative position is slightly more difficult.
Of course, the best solution is aspherical mirrors, but for some reason they're not allowed in the USA.
The diagram in that article underestimates the viewing angle of the various mirrors in the car--my rear view mirror has far more than 90 degrees FOV, and when my side view mirrors are adjusted the "new" way I am just barely unable to see the side of my car.
How so? The only possible issue I can see about that solution is that you can't see your own car in the side mirrors and thus judging relative position is slightly more difficult.
Of course, the best solution is aspherical mirrors, but for some reason they're not allowed in the USA.