After I known bitcoin, I think is the best that promise huge profits, so I took the decision to make the bitcoin as one long term investment.
as what? what field you chose to make bitcoin the long term bitcoin. bitcoin it self a long term investment. but you still need to choose something to do with bitcoin.
only holding bitcoin is good but keeping them circulating in profitable businesses is much better than keeping them in wallet and idle.
I think holding bitcoins may be a good long term investment provided that you are able to increase your coins through purchasing more bitcoins with your fiat money. This way your dollars will be deposited in a very profitable investment with a promissory future.
But if you are not interested in increase your coins through purchasing, perhaps you should consider the possibility of investing them in some of the different possibilities that forum members have shared here.