Thats the best investment than having 99% of altcoins on your portfolio. I admit that ive made a really bad decision not putting bitcoin as my priorities in investment cause I was expecting that some altcoins would go higher like a boom. Mid year last year I started putting 50% of my funds on bitcoin and will continue this year hopefully.
It is not necessary to put all your assets in bitcoin, you can also allocate in altcoins, but need to prioritize bitcoin for your portfolio. That is absolutely necessary. I see nothing wrong with OP putting an entire portfolio in bitcoin but it would be a waste if we missed out on potential altcoins. So I will only put 90% in bitcoin, the remaining 10%, I will look for potential altcoins.