His primary position in college was as return man. This will probably be his primary position in the nfl. There's speculation he can do other things like play cb or whatever else. No one is talking about his enormous upside as a WR and so I believe its safe to say that "nobody thinks he was drafted to play WR". That doesn't mean its impossible for him to play some WR downs. I'm sure he will (occasionally) if he succeeds in the league, but that's not really what you want him doing or why you took him. My mother in law is a huge Ray Ray fan because he would make some special plays, often of a gimmicky nature. I don't consider this sort of stuff as "playing wr" even if that's how he might line up sometimes.
Steve Tasker contributed plenty at wr when you google him that's the position that comes up for him, but nobody thinks the bills kept him on their roster to play that position.
I don't know why the Bills drafted him, but there's lots of reasons that stand out to me and non of them are because they want him as a wr. Maybe they want him to play corner. Maybe they just see a special athlete, maybe they think he'll be a good returner. Like I said I don't know. But to me it seemed that lots of people were talking a lot of **** about the pick as they compared him to other wr still available, so I wanted to point out that his WR skills (almost definitely) aren't why we picked him.