Every investors and traders ought to have a reserve fund so in case of an need for that. Many people that called themselves traders and investors have lost money in the market and have not reserved fund to fall back to so they can keep trading or investing. Anyone can loss when investing which is why it's good to invest in projects that are trusted. Traders are the ones that are likely to fall to this kind of issues because they are opened to greed. We can make money in the crypto market and still lose depending on the kind of investors that we are and what we are investing in. There are some projects you might invest in that might not be profitable which is why it's good to have a backup funds when the need arrives.
I feel you don't really know the purpose of reserve funds, reserve funds is for planned expenses so talking about using it to cover up when you lose money during trading or investing in shitcoins is not it purpose because these are unexpected events and I think your emergency funds will have a major role to play here instead of your reserve funds. Saying that investors can lose money depending on kind of investors sound to me that you are referring to traders as investors, but rather it should be depending on the kind of project the investor invested in like shitcoins.