My stock phrase is "Don't make it complicated"
Some people may say that aiming to fly on the boundary, relying on very accurate navigation, makes things more complicated than staying a reasonable distance out. Note the use of the word 'reasonable'. Where ground features abound, that may be very close. Elsewhere, it might be further out.
Some may also argue that overly concentrating on your navigation may remove focus from other, potentially more important, flying tasks. Even relying on your GPS only to keep 'on the line' on a VFR flight in essence makes it into an IFR flight... or at least it means having your head in more than necessary - as an example.
As always in life, just because you *can* does not always mean that you *should*.
B.