As you know binance is one of the fast growing growing exchange out there and it has already become global exchange and if they continue with same pace then in 5 years we might see binance as majority holder in exchange space then bnb will automatically rise in price so it is safe play to accumulate it and leave it for few years to get massive profit. Binance is continuously working to introduce something new to space so we might see other usage of bnb soon.
Possibilities of BNB making a hard pump are much greater. But in case there are any internal issues which might make some of the users lose their funds than I think that majority of people might stop using binance and BNB coin. This might be something which might dump the price.
We can't exactly predict the future of any coin as even 5 years is a long time span and in this time anything can happen with the high volatility markets. If binance gets hacked, etc than many of the users would lose their faith from the exchange which might even lead for panic sell of BNB which is never good for the price of any coin. BNB would dump in this case but the chances of this to happen are quit less.