Bitcoin,there is no doubt in it that the price of bitcoin keeps increasing on the long term. Altcoins are good for short term investment but for long term investment, Bitcoin is the best option. What I do is buy bitcoin and hold it for long term while i trade on altcoin for short term.
Day trading is doubtlessly a good way to increase the capital on daily basis but altcoins is not a good option. I think bitcoin can be much profitable for this. It value increases more than any other digital currency.
It is not only safer to invest in bitcoin but it has also the most potential among all the crypto coins. We can see the past figures and I am sure nobody will deny me.