I've not been using DOGE to transfer for a while but when I do - I tend to sell at 1-2sat higher than I bought and make a small profit on the transfer. Market conditions have to be right for that or you could make a small loss instead however.
Other times I've needed to transfer whilst BTC tx speeds were slow and used DOGE to get the funds across faster
you are talking about trading and that is buy low and sell high,that is different story when we are talking about transfer money that is the case need to complete as imidiately as possible.
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There is always the risk that the price will be lower or higher on the exchange you are moving to - so you may have to take a loss/gain during the exchange