Profit and loss are connected with every business. Whatever business you do, you do it with the intention of making profit. No one ever invests in any business with the intention of loss. It is certain that wherever one invests without thinking, there will be loss.
There goes the first time businessman that have been lucky to have it the profitable way but majority is expected to set a loss. That's how business goes and that's to be expected whenever you start one. Because it's full of uncertainty even if you know what you're doing.
Any business is always started from a small level and scaled up after gaining experience and understanding the market. Since the crypto currency market is a very volatile market, the prices are not always the same but always go up and down. This is the reason why always invest money here that is more than you need.
You said the opposite, invest only the money that you don't actually need which is just like a spare money for you.
Maybe when you need money and you want to withdraw your money, the market prices have fallen and you have to make a loss.
This is the good thing on this market, there's no lock period unless you avail those exchanges and wallets staking features that your asset will be locked for a certain period of time.