Which coin do you think would have a huge pace of growth in 2019?
This is a more realistic comparison between coins (at least not being compared with Bitcoin) but I think ETH will continue to rise more than BNB. The reason being of ETH's advantage of contract by other projects using the platform coupled with it being a payment option like BNB.
BNB's use is limited to Binance exchange and its DEX.
This isn't accurate. There are several other exchanges where BNB is traded. You can find that list here
https://coinmarketcap.com/currencies/binance-coin/#markets