You can investment your money in land, house, gold, silver, stock markets, fixed deposits & savings in banks, start some business or invest in some business (like restaurant, hotels etc..)
Actually Bitcoin and crypto currencies are not required/unwanted

I agree with you about 7 safest way to invest in our money and its good to do but for land and house need so much money to start it. If we just have $100 then its not enough to start so i will prefer to invest in cryptocurrency.