About what you said at OP:
I read somewhere that TrustWallet user has access to the private keys of each coin supported by the wallet.
This doesn't happen. Binance or Trust wallet has not access to the keys, which are only stored locally according to their website.
I said that a user of the trustwallet has access to the private keys of the different tokens he owns.
About Binance, they said they don't have access to the keys which are locally stored according to their website. But we should always remember that trustwallet connect to nodes and servers owned by Binance, so no one can verify/confirm if they are really in safe hands. Personally, i don't feel that safe with this kind of wallets so i don't afford to use it with big money.