Not sure how much money you're trading with, but 50% for trading is too much of an allocation in general; well, unless you're only trading with money that's so small that you're fine losing.
I will also advise traders to use lower amount of money to trade.
But it depends on the amount of money, strategy used and the margin ratio. As low as 1x margin ratio, the percentage is not still advisable, but can be advisable for 0.2x or lower margin ratio, and also depending if the amount is big or not.
Generally advisable to minimize the amount placed on trading. Even if not thinking about trading, another thing to think about is if it is worth leaving the 50% on an exchange, it does not worth it.
I personally don't call it "investment" because it is trading and I don't consider trading as an investment. It is either a job or in case of altcoins it is mostly a gamble.
He is mistaking swing trading to short term investment but they are different. @Kaliandra, any trading that is not up to months is still trading and not holding or investment. If you have open trades for some days to many weeks, it is still swing trading.