From my experience, it is profitable. I prefer short term than long term though in some instances I am forced to hold when prices don't go my way. My technique is that when the current price of altcoin is below by 10% its average price, I buy and then when prices go back to its average value I sell. I don't mind making many 5% trades per day.
I know sometime short trade is profitable but it need more experience and high skill.
You said that you will have only 5% profit but sometime the strategy not always come as our rule. What will you do if the price goes lower from your buy price and it takes more than a month? Cut loss or hold?