Have you read the relevant FAQs
Export/Import: move calibre data from one computer to another?
How do I backup calibre?
I don't see them as alternatives. If you want something to help you recover from a disaster - your house burns down - then an off-site Export Archive may be useful.
My suggestion is to keep doing what your doing now, with the addition of backing up your configuration data.
And consider use of a folder/file synchronisation tool to maintain the copy (mirroring) - see
Comparison of file synchronization software - Wikipedia. I use Goodsync. FreeFileSync, Synctoy and rsynch are popular amongst the calibre user community.
The advantage of these tools is that, after you've done the first copy, they only copy what's changed. So, they are much faster than copying everything every time - which means you're more likely to run it - maybe even every day
BR