That is flat out wrong. It depends on your trading style. The leverage a prop firm will offer you is a huge advantage when used correctly on some longer term trading styles, like arbitrage.
Also keep in mind the ability to compound your money faster when you can effectively use it in more places at once. I'll give an example. Say you swing trade stocks and risk 1% of your account equity per trade. You also trade futures, maybe over many days as well. You have $50k to trade with. In a prop firm with, say, $15k in capital, you can trade your stocks and risk $500 per trade as if you had the $50k in your account. If you have a rare, longer than normal drawdown, you know you have the money to back it up. But in the meantime, you still have $35k to trade a futures account (or buy revenue property, or some other kind of investment). There's also the advantage of not having to pick which of your valid trade setups you'll take based on margin requirements. If you have a positive expectancy system, ideally you want to take every trade that your system signals. In a retail account you might not be able to do that because of margin requirements. Not a problem at a prop shop.
I trade mostly longer term strategies at a prop outfit because I can do it without tying up a lot of capital, which I can put to use elsewhere.
Also keep in mind the ability to compound your money faster when you can effectively use it in more places at once. I'll give an example. Say you swing trade stocks and risk 1% of your account equity per trade. You also trade futures, maybe over many days as well. You have $50k to trade with. In a prop firm with, say, $15k in capital, you can trade your stocks and risk $500 per trade as if you had the $50k in your account. If you have a rare, longer than normal drawdown, you know you have the money to back it up. But in the meantime, you still have $35k to trade a futures account (or buy revenue property, or some other kind of investment). There's also the advantage of not having to pick which of your valid trade setups you'll take based on margin requirements. If you have a positive expectancy system, ideally you want to take every trade that your system signals. In a retail account you might not be able to do that because of margin requirements. Not a problem at a prop shop.
I trade mostly longer term strategies at a prop outfit because I can do it without tying up a lot of capital, which I can put to use elsewhere.