My grand mother has a 50 tr old nephew(if you can't put two and two together,that would be my mom's cousin,which extends to my incle)who is deaf.He turned deaf when he was a lttle boy.Now,they didn't have money or anythign,so he basically never went to any schools and all that.He and his mom can communicate and understand each other perfectly well.The reast of us can never get a thing he "says".And he's always telling these stories,gesticulating and laughing and stuff,and we just act like we know wussup so as not to look rude,and he's so into telling stories.I guess it runs in the family,coz if (especially when we were kids)you do something and grandma is reporting you to your mom,she's gonna embelish that story so much it's like you killed somebody,and all you did was take two shillings(you need 78 of them to make a $)to buy candy.Anyway,we can't understand this guy.And he doesn't use standard sign language.
Now,if he knew and used standard sign language,we'd learn it as well,and we'd be ablr to talk to him,and him to us.But now he uses some version that only him and his mom understand.Because I guess they're the ones who develpoed it bewteen themselves as he grew up.
To me,sheet music is a bit like sign language,musically.Knowing the official Kenyan sign language is an asset.But only as long you're dealing with fellow Kenyans.There's (I hear)British and American versions.Then there's the international sign language.Which anyone can learn,and use to speak to whoever from wherever.
Sheet music is like this standard.Tab is an asset,fine,but like someoned mentioned,you can't use that knowlegde on another instrument.Not so with sheet music.
So if you can,learn it.