Having read the previous posts on this subject begun by another user, and noticing that a related query from 2012 (GRS and prostatectomy) had led nowhere, I thought I'd add something to the discussion.
Perhaps this only applies to a small number of us, but another reason for considering a cosmetic,as opposed to functional vaginoplasty is a prior prostatectomy.
It is my understanding that removal of the prostate, as treatment for cancer, also involves surgically cutting away the muscular sphincter of the bladder neck ( the main valve preventing you from weeing yourself). Patients have to try and learn to use the muscles of the pelvic floor ( which previously only had a supporting role in keeping dry) as their sole means of continence.
The urethra, vagina and rectum all pass through the muscular sling which is the pelvic floor. I would imagine that, post prostatectomy, creation of a vaginal canal as a new breach in the pelvic floor would lead to incontinence as the pelvic floor muscles have to relax sufficient to allow penetration/dilation
A further issue is that the prostate lies close to the rectum, and scar tissue from any prostatectomy surgery can make fashioning a vagina problematic (this was gleaned from one of the UK SRS surgeons, via a third party).
A further factor to consider is that prostatectomy means the erogenous prostate has gone, no longer lying adjacent to the neovagina. Possibly then, penetrative vaginal sex would be less pleasurable.
I'm not a surgeon, just someone who realises that cosmetic vaginoplasty may be an option for me, having had a prostatectomy.