What is the point of Jon being a Targaryen?

[Sansa123]

So ever since I read the books and figured out Jon's parents I thought that the reason why George made him a Targ is so that after all that time Dany spent proclaiming she is the rightful Queen because of her last name it turns out she is actually not. She doesn't take that revelation well and turns on Jon who is forced to defend himself, probably wins and becomes king.

 

Meanwhile in the show they are taking the opposite path, having them fall in love. She is clearly smitten and while Kit doesn't play Jon as if he likes her we still had Davos say that he does, so...

 

My question is if they really end up together then what is the point of Jon being a Targ? The title Works either way, if he is a Snow the title is about both of them and if he is a Targ the title is about him alone. I thought George made Jon a Targ so that it can be a game changer in terms of who belongs on the trone when it's revealed and sure, they can still become enemies when it's revealed in the show, but with so little episodes left there doesn't seem to be any time for that. All signs point to them hooking up, and then what? My guess is they end up on the throne together or one of them dies fighting WW, but in neither of those scenarios him being a Targ actually makes a difference in the story. So why is he a Targ then? Just so he can ride a dragon?

 

I would love it if they found out about his parentage at Dragostone and Dany tries to kill him right then and there so she can be sure she gets the throne, but a dragon saves him and they escape, then the First part of the next season is Jon vs Dany and the second part is everyone vs WW or she actually kills him and then Sansa and Arya avenge him. But then his ressurection would be pointless. I am 99% he lives until the end.

 

Share your theories and opinions on why did George make Jon a Targ and how will it affect the story.