Bitcoin achieves real value by being used for buying and selling real goods and services. Major alt-coins achieve value by promising to being successful as bitcoin alternatives, e.g. fail-safe for things like hard forks, algorithm compromise, etc, to a lesser extend also achieve value by being used in real life transactions. Junk coins achieves value solely by promising to be next being pumped and dumped.

Most junk coins have to be bought with bitcoin.

I am mining altcoins to sell for bitcoin. People are free to choose their currency. I only believe in bitcoin and litecoin, so whenever the other coins get too valuable, I mine them so that I can short them and long bitcoin. When I mine litecoin I hodl!