I cannot say that fresh coins are always profitable. It is just because none can predict which coins are good for investment. Generally new coins are hyped when they hit exchanges. As a result, their price soars for short term. If you are smart enough to sell when their price gets soared, you can get much profits. Otherwise, you can go for established coins.
Well it is a good strategy, the right time of selling is much profitable in trading as there are many new coin whose price only increase for a short period of time and selling at that time is always profitable whatever coin it is, but if you miss that right time then it completely loss because new coins mostly die after extremely big dump. I will personally suggest that XRP is very beneficial for short term trading.