This drop across the board (all major cryptos fell) felt more like a correction and/or somebody cashing in interest and it will fully recover. Bitcoin (despite some other cryptos being - imo - superiour) most probably will stay in leading position and become more stable this year. I'd say, that we'll see swings like that less and less (given its market cap - even by total supply). So unless some other altcoin overtakes BTC as market cap leader (not that hard) and as crypto icon (very hard) it's will be very safe to short from time to time.