In my opinion, the most important thing in choosing a crypto platform is high and strong security because this is about protecting the assets we own. Rather than just looking at the cheap transaction costs but low security, it is very risky. So to choose a crypto platform is primarily security and then followed by other factors, such as the user interface, or available features.
If I understand you correctly, by crypto platform you mean an exchange right? Where you can trade or do some exchange with your coins and then send to external wallets right? I don't think this is something you can debate, it's a personal something you need to choose. If you are a Ether lover and you want to withdraw Ether, you need to pay ethereum fees which is the highest im altcoins and if you need USDT, you will be paying $1 or less depending on which network you are using.
You don't have anything to do with the security of the platform, your priority is to buy and trade and move your coins out of the exchange, it's as simple as that. What the exchange does about the security of the platform is upto to them, it's not your responsibility to take of care of the assets but you should do the basic needed safeguard your tokens from hack and hijack.