A better alternative would be lending to an more reputable exchange. Yobit's not a great exchange in my book from past experiences with them (delayed withdrawals and deposits, wallet problems all the time, etc.), but loaning to an exchange can sometimes be more profitable and more secure than using Yobit's investbox. I've seen numerous negative reviews from a thread about the Investbox (https://bitcointalk.org/index.php?topic=1922048.120), and I wouldn't recommend continuing to invest there. The vagueness of the Investbox's description doesn't exactly help.

Note that there's always risk when your coins are outside a wallet that you control. I would not suggest putting all your eggs in investing to exchanges. Only invest what you can afford to lose.