Thats actually the best thing any profound investor can do for himself, because diversifying your investment to different area actually increases your chances of gathering better profits and like you said also reduces the possible loss rate that you might inquire to your investment. Although its not a compulsory thing and it also depends on the budget in which the investor is going with because you can't make different invest if actually your capital money isn't enough.
Before investing, it's wise to make better plans on how you want to carry on with your investments, how you want to diversify, how you want to roll over, and more. For instance, if you are earning like $2k a month and you decide to invest $500 in Bitcoin every month, you can also save $500 every month that could be invested in other things like real estate, stocks, or even a bond. Some people don't just know how to go about investing. Again, one can even invest in Bitcoin and earn a huge profit during the bull market. The person can still sell some of his holdings and invest in other things. In investment, if we invest and make a profit, we are supposed to reinvest the profit to yield extra profit. That's why some people are more successful because they understand the principles of making different successful investments, despite the fact that not all will be very successful.