That can only be for a small handful of songs though - where the top note is right at your upper limit.
I mean, I'm an elderly untrained singer too
, and I do understand that a half-step lower can make a song more comfortable. But the number of songs I sing (or want to sing) where I'd need to tune the guitar down a half-step is approximately ... er ... zero. I really can't think of any.
If the top note of a song is too high for me - even if only by a half-step - I'm going to be lowering the key a lot more than a half-step, so as that top note is well within my range; which usually means transposing the shapes, and maybe using a capo.
Sometimes I will keep the same shapes (if they are important to the song) and use a capo, taking the vocal down an octave - e.g., capo 5 frets up, vocal 7 half-steps down. (That's not common though.)
I guess, for me, I prefer to stay with EADGBE as much as possible, partly out of habit, mainly because it suits the band I play in (they tune to standard too). But I have no problem transposing chords to other keys, and I understand that some do.
Absolutely! Good vocal exercises ought to take care of a half-step anyway
- plus they will strengthen your voice in other ways too. Go for it!