Even big bank are hacked or becomes bankrupts. Security is important, the price of transaction is important. And it is hard to say what is more important - the cost for transaction or how it is secure?
I think that security of the platform is more important because is the platform is not secure you can lose all your money but if the price of the transactions is big you will lost only this price. But big transaction costs can make all kinds of business unprofitable.
Only time can show how secure is the platform. The platform can look like secure but not to be secure at all. How to understand if the platform is secure or not?