I am not asking this to be transphobic or anything but I had this debate with myself at 2 o’clock in the morning and every time I remember it I can’t focus.
On one hand, it is what they want. Let’s assume it causes no harm to them or any unforeseen circumstances.
On another hand, it would erase their identity as trans people. At the extreme you could consider it a genocide, since turning them into what they want would mean there is no more trans people and their unique identity is erased.
Surgery is terrifying! If you have no or mild dysphonia then the idea of someone removing part of you or otherwise changing it is quite disturbing even if the end result is appealing. And that’s if the end result is appealing - it isn’t for everyone. Gender isn’t necessarily tied to what’s in your pants at all.
Well, my hypothetical scenario implies an instantaneous 100% change with a 100% functionality, at zero cost, specifically for that reason.