The investments in this category are a benefit for all bitcoin holders. Here you can earn bitcoins with the ones you are holding. You can increase the amount of your bitcoins in addition to the price gain instead of leaving them on your wallet.
There are many different possibilities of investing to earn bitcoins. Really interesting is the principle of a masternode pool. A specialized company is setting up many different masternodes, so the resulting pool is quite diversified, where you can participate.
Another opportunity is an automated crypto trading, where professional traders or a computer is trading for you. Last but not least I have to mention crypto mining.