With people who love the long-term stability, and see it like as a savings, put it all into Bitcoin is a wise choice and absolutely safe
In my view, there is no safest coin for investment, even it is Bitcoin. Who knows what will happen in the future, surely no one can guess it. That's why some people advise diversifying your assets. I think what OP said is wiser than to put all money on Bitcoin. However, it is your choice, you may have your own view and wants to focus on a single coin only.
This topic should be put on Bitcoin Discussion :
https://bitcointalk.org/index.php?board=1.0