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 freebitco.in is one the most reputable sites, it seems very risky to me to store 10 BTC on it; even storing it on a legit exchange as Kraken or Coinbase is never recommended. Yes, the interest would be very nice but just seems way to risky for me. What if your account get compromised or stuff like that?