Currently I can't suggest for you to go with ICO or only with Bitcoin because because here matter is not of investment but of smart investment that you should do for better profit and low risk .
No doubt that ICOs investment are much profitable business but we should have investment in ICOs project otherwise you may face scam . Next thing is that you should buy with few amounts of money for btc and also hold another better coins like etherium , dash to amke lots of profit for future .
Here if you will buy Bitcoin only then I don't think that you will be able to make big earnings than what you can make with the investment in another altcoins like etherium , because with etherium investment the amount of Bitcoin will increase but with Bitcoin only Fiat value increase , so use your mind more smartly before investment directly with blind eye .