I suggest you to withdraw immediately after you finish your trade. They're not trustworthy enough to store your assets.
Maybe you mean it is not a safe place to keep your assets, saving assets in an exchange especially for the long term is not a good thing, because when the exchange is hacked, our funds can be lost there.
I have traded on Gate.io and KuCoin, however for now I prefer KuCoin, I only trades small amounts so I don't need to do KYC, KuCoin still trustworthy
It is much safer to do KYC in trading on this exchange to secure your account when there is a problem with KYC, we can provide valid data when a problem occurs, especially when hacking occurs on the exchange, of course the funds will be lost but that is all the responsibility of any exchange. those who get hacked can do that.
But obviously I have never deposited an asset for so long on an exchange just to trade it when the market is busy it means a high rise and there I feel a big deposit back to maximize it.
Gate.io and my Kucoin have been using this exchange for a long time and are still safe.