Certainly, it's possible that any guitar may have resonant properties when tuned to frequencies other than 440. It may sound "better" or "different" or "more resonant", etc. And that may be desirable.
Likewise, it could be a decision based less on the resulting pitch but the resulting tension. Again, some instruments just may play better (different scale lengths for example) with different tensions (and ones not necessarily available in the set of strings itself).
If you ever have time, here's an interesting experiment:
Put a capo on the first fret of your guitar (or all of your guitars!) and play for a week or so.
At first it will sound kind of higher and tinny, but when you take the capo off a week later, it will suddenly sound HUGE.
These jokers who are out there tuning to 441 and 442 (violinists in orchestras for example) do so becuase it's "brighter". Well it's only brighter until you get used to it!
There are also plenty of rock guitarists who tune down to Eb or lower becuase it sounds "bigger".
But what has happened is they get used to the pitch level, and have to keep going down further (or up further in the case of classical violinists).
Your biggest reason for staying at 440 would be to match other instruments using that standard.
I usually just tune my guitar to where it sits - in tune with itself rather than tuning it specifically to 440.
Sometimes I'll check and find it's drifted almost a half step low over time, and then I'll often bring it back up (just so it's in tune with my other instruments) and let it slowly drift down again over time, just tuning it to itself as I play.
My preference is for 440 just because I play with so many other musicians who use that standard.
But I see no reason for it to be set in stone.
This nonsense about the 432 or whatever and all that junk is a little silly though.
And, FWIW, a lot of rock bands tune down to Eb (especially local club/bar circuit bands) because it makes it easier on the vocalist.
It's a little bit of an amateur/hack thing though.
I mean, there truly are people whose voices have "breaks" in areas where singing in certain keys and/or tuning standards are better for them.
But really, a half step shouldn't make that much difference for anyone other than someone who is really just singing at the top of their range constantly. And if that's the case, maybe the keys should be changed or different material chosen.