A coin can find its own market niche and be a market leader in this niche.
But you are right, many coins which are trendy now, will be forgotten in the future.
Short term strategies on Altcoin markets are very dangerous, people can easily lose money hoping to make a quick buck.
In my opinion, upcoming months will be important for MOON. Maybe it's a good idea to have a short term portfolio, but also a long term portfolio (in paper wallets).
The key here is that unless these Mooncoins (and nearly a thousand other altcoins) are not exchanged for bitcoin which can then be spent in the online and real world, they have no value.
Mooncoin has nothing in benefit to offer over the other nearly 1000 altcoins out there. I think all of these altcoins will be useless with the exception of bitcoin and maybe another two or three in the future.