It basically makes sure that one is the correct gender on the registry of marriages, and on ones death certificate.
So two things that the trans person doesn't see (except when signing the register when getting married).
Does it actually say a 'gender' (or sex) on the marriage register? Because it doesn't on the certificate. And nobody ever sees their own death certificate, obviously.
Sorry I wasn't clear, I meant: get married in dignity and die in dignity. Where dignity means "as the correct gender"
I don't think there's any restriction on what someone can wear to their own wedding, so if a male wants to perform femininity at his wedding he is perfectly able to (and a female can perform masculinity).
I'm pretty sure gender performance would be pretty low down someone's list of important things to think about when they are dying (but I could be mistaken). How does someone die 'as the correct gender' anyway?