As the Bitcoin network experiences transaction congestion and higher fees many people have considered alternatives to avoid these issues. During transaction traffic peaks, a few cryptocurrency supporters have recommended using altcoins to save money from bitcoin miner fees and speed up settlement times. However, using an altcoin to save a few cents on a transaction may be more of a hassle than you think.
read more:https://news.bitcoin.com/using-an-altcoin-to-save-a-few-cents-may-not-be-worth-it/
Ya it is true that due to bitcoin network congestion some of them are trying to promote the altcoin to be traded but still their are no direct buyer and seller of this altcoin in other format apart from Bitcoin conversion so until the altcoin are not directly buy and sell in fiat currency only bitcoin can be used. First the altcoin should start trading in fiat currency and users should start accepting it then only this way of transaction will be usefull