I believe that kinda depends on the level of savings you have and you can invest.

If you mean is it okay to get a loan from a bank and put it all on a bitcoin, that is never a good idea, not now not ever. However if you are asking if you have $100k in your stocks account and you want to take out $20k of that and put it on bitcoin, well yeah that is a great idea. It is all subjective on the amount of money you have.

A person with a house all paid, a car all paid, some stocks and great investments can take out a little cash and put it on bitcoin, he wouldn't be hurt in any case, a person who is in debt for some stuff should not focus on investing in something as volatile as bitcoin.