On the issue of using USB items with Crossover, there is a patch set in the development repository of Wine for USB driver functionality, it is used by some fork projects to provide support for a few USB devices (namely early software-based WiFi adapters), but has not qualified as "reliable" for the Open Source build of Wine or the Crossover build of Wine.
If I recall correctly, the problem is that the patches interfered with many "soft" drivers that are used to help handle security and copy-protection functions of programs, as well as the cheat protection of games.
For USB scanners on Mac, you should check the various 3rd party drivers. Especially the Open Source ones.
For Linux, check the SANE project. It rolls almost all the Open Source drivers into one.
It is unfortunate that you cannot scan directly from programs in Wine.
The recommended solution is to scan to a file then utilize open-with to open it with your desired software in Wine.
I highly recommend that you try some of the Open Source software out there like Libre Office.
However, many people are stuck with Microsoft Office because of dependence on proprietary Microsoft Office plug-ins utilized by their employer. That is the whole reason Codeweavers works so hard to make Crossover work with Microsoft Office, and why it is considered a primary goal program.
p.s. Upon review, the SANE project has drivers for the vast majority of the SnapScan scanners. Currently WiFi access is not supported, but otherwise almost all of them run well according the SANE website.