A huge number of orders are liquidated every time bitcoin goes the other way against expectations, stop losses would have saved this money, but alas, they went to the exchange.
With altcoins and tokens trading you must use stop loss because at some instances you feel emotional about your investment in some particular coins and you carry them for too long while you should have sold them a lot earlier given the market movement and the project development. Stop loss is a good feature that keeps you within reality and you ensure that you are not trading emotionally. Of course at times you will feel like you could have saved few months longer and earned profit instead of loss but that is how trading goes, overall stop loss will benefit you in altcoins trading, that is my experience and estimation.