It depends on the situation if i lost a significant value in bitcoin due to bear market and the decision came in it depends on how much I can save in the projected bear or how much I can profit in the coming bull. It is both good and bad ideas. In some situation, selling altcoin can be accepted and you can save your money. However, in some other cases, selling altcoins can make you suffer a huge loss or miss the opportunity to earn a great amount of money