Lots of coins promised that they can provide you interest each day but it depends on the price of BTC. When the BTC drops hard, you are going to lose money. Lot of people believed that when the BTC drops then the altcoins would increase which is not true in my opinion. We have seen two crashes in January 2018 and Feb 2018 , so the altcoins depend on BTC and look for strong fundamentals.
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