As long as the problem of transferring funds will be sorted, I don't have an issue as I know I will accumulate the bitcoins and withdraw when they have a good amount. This even saves on the withdrawal fee
I know that some people with experience with online wallets will sometimes worry that the wallet and the balance and the website and every thing will disappear overnight. It can happen, but Yobit has been there a while and you should be fine. Although I do transfer out once per week to a cold wallet just to be safe.