It's not really the same thing. When someone goes on a talent competition show and his story is "I was Amy Winehouse's friend" it just sounds like a cheap desperate way to get some votes. I just think there's an appropriate place and way to talk about her, and his was not the one, atleast not for me. A lot of her close friends were ambitious singers but none of them ever used the friendship to familiarize the public with themselves... Tyler did, and multiple times now, so... I just don't like it.
I don't think he did it to sell Amy out or to win 'The Voice'. Personally, I think he said it once when he auditioned and after this the producers always asked him to talk about it. Before 'The Voice' aired he tweeted that he's sick of talking about Amy the whole time and that it makes him sad (I don't remember the exact words). Not sure about this interview, though, maybe he didn't even talked about this, we all know untrue storys can be written..