What about 10BTC investment? It generates 0.001BTC daily that is equal of $37 daily or 1200 USD monthly. It's more than enough income for those who live in poor countries and still a very good addition for those who live in rich western countries.
Not bad at all. Monthly money made from that can be easily used to cover up monthly bills in any under-developed country that has its local currency in red compared to the USD.
It can be a good method to hold those coins instead of keeping them locked in the wallet. Additionally the site allows you to withdraw the money any time you want. The only deterrent is the counterparty risk - meaning that you have to trust the opposite party in this case freebitco.in's owner and that they would not scam you, which we can all be sure that they would not.
While I think that it's safe to keep your coins on Freebitco because this website has proven to be trustworthy, honest and fair since 2013, we still shouldn't forget that not your keys means to not your coins. If I were an early adopter who bough bunch of bitcoins when price was low, I would simply hold 10-20 bitcoins on freebitco account to cover my monthly expanses and more.