Spam is unsolicited correspondence. Cold emails are unsolicited, therefore are spam.
If an email ticket ends up in the wrong account why would you trust them with your hosting business?
when using a ticketing system a unique mailbox is created for the issue, only the agent that was allocated to the issue has access to data.
It is also possible, if I consider your suggestion to run MySQL directly on the VM - then the two containers above. This would be cheaper, wouldn't it?
using a vm you'd save about 30usd/mo
i could provide a configuration that you can run directly on your machine. drop me a line if you need help, i'm @andreicon on twitter