However, in a scenario where BNB is never used for anything else, there are more and more trades and volume on binance every single day, there isn't a single day where nobody trades on binance, every day millions of dollars changes hands there which means they will get trading fee and many of those traders uses BNB for trading fee payment as well. So all in all the need for BNB will never be gone, it could shrink but will never be gone.
We cant conclude though on what would be its price for 2020 but if bull run start of this year then this coin will go to the same path yet theres a significant demand and usage once again.
For now if you do have the money to spend or invest on BNB then its still a good choice but at least you should always consider when it comes to risk factor.