I wouldn't argue that Intuit is, or is not a good company, but their software is running on a general purpose operating system that is structurally deficient so far as security goes. A Point of Sale terminal can, at least, be dedicated to nothing but dealing with cards and the security required to keep things safe.
I use Quickbooks as well, but I have no idea whether the backup file is encrypted, or not. It is password protected, but that is not necessarily proof of security. And the 'active' version of the company file, is that encrypted?