Although Bitcoin has taken up 40% the coin market. But is it more worthy to invest in bitcoin? Since bitcoin can never replace the paper currency for the moment due to many complicated reasons, and most bitcoins are already acquired by a small sum of people. So if a kind of currency can't be circulated, what's the meaning of that coin. When it comes to ICO, and the release of altcoin, it means that you are investing in a company, you are holding equity in the company. If you think this company will have a bright future, it's always worthy to put your money in.
Unfortunately it's not as easy as this. Bitcoin has the first mover advantage, a well known reputation, a solid and reliable team and product. It's also widely accepted as the currency of reference in crypto.
Now bitcoin has disadvantages, as you mention the coin re partition is not perfect, it's tx/s is not scalable in its current state and it lacks many features that other altcoins bring to the market.
A good portfolio is the perfect balance between serious altcoin projects and established currencies such as bitcoin, that no matter what will always hold value.