While this guarantees that you will get out as soon as it hits a desired priced, there's the problem of leaving your coins in some exchange. If it's a shitcoin, and it's still listed, chances are this coin is listed in one of these dodgy altcoin exchanges. I wouldn't feel safe leaving any relevant amounts of money in say, Livecoin.net, cryptopia, or any of the other more obscure exchanges.
I dream everyday with decentralized exchanges so you can keep sell orders indefinitely and safely. Having to think about if it's worth the risk with centralized changes sucks.
I think we will finally get decentralized exchanges next year, maybe 2019... or possibly 2020 as of totally late. They will work on the lightning network, so you will be able to make buy and sell orders without actually holding your coin outside of your wallet, they will be like smart contracts of sorts. It's hard to explain but the point is the future is great for bitcoin and crypto, since we will cut the middleman of scammers (all centralized exchanges will eventually fail). Im now a bit worried about what could happen with Poloniex and Bitfinex if the Tether scam is real.