A VM that is connected to the internet is exposed to hacking, and the fact that your computer uses VMs will not immunize it.  A cold wallet has no connection to the internet. Ever.  Keep substantial amounts in a cold wallet.  Discretionary Bitcoin used for currency needs can reasonably be kept in a wallet linked or occasionally opened to the internet, if the wallet is encrypted and redundantly backed up.  To sum up, VMs are not automatically secure.  Use hot and cold wallets after deciding the balance you want between security and convenience.