I don't understand why you want the two coins to be big, and my mercatox has experienced trauma when transacting there, it's been a long time and for now I don't know what the mercatox looks like, is the condition still the same as before or not
It means that this coin doesnt priced yet and you are waiting for a coin that is not yet added in exchange. Anyway it is your choice. Besides you I want to invest in Bitcoin and Ripple because bitcoin is the leading crypto and Ripple is the fast growing crypto in the market and its market cap is increasing day by day. People like to invest in Ripple because of low price and high market cap.