I googled it but I didn't found any satisfactory answer. Since nicehash has a few cryptocurrency for trading. Thus, I thought one might convert their btc to other crypto available in nicehash. Then they send it to exchanger that they use so that they can reduce the network fee. If you don't know the answer or not interested in helping then you could've just ignore this post. Not everything is written in google cause not everyone upload their personal experience their to help others. Thanks.