That coin flatlined for years. What happened and how do you know it won't happen again?
If you can know something for sure you don't have half a million marketcap. Big risk big reward, simple as that. ETH has flat for long time before bull run too. Mincoin not even has reached its all-time high, there is definitely only way to go up: fast growing communtity, new devs, new exchanges, mature blockchain. There is no more coins with infrastructure and such a low marketcap.
Altcoin's best investment for this period is Bitcoin Cash. we can see in its development that is in Cryptocurrency market which gets progress which enough increase this rapid give high profit and bigger. and I see for Bitcoin Cash is very potential to continue to experience the ever-increasing development.