An investment is always better because your money grows with time. But you should not invest 100% of your money, you should always save some of it and invest a part of it. It is always hard to take risk but you cannot gain something without a risk.
We better to invest our money in something that continues to grow in value every time like gold, property or bitcoin. If we only save money then its value will only decrease due to inflation, I agree with your oppinion about not investing 100% of our money, succesfull people usualy inveat some of their money on any type of investment so that if one fails they will not lose all of their money.
Everybody always has a method to uses and makes profit from Bitcoin, no one has same idea 100%. If you are holder, it not means other traders also holder like you, because on the market still has traders want to make profit every day.