First of all, I am not currently using inSync, because I do not store anything on Google Cloud, but I am VERY interested in support for OneDrive, and this is why:
I have an Office 365 subscription active for about 3 years now (1-year keys become extra cheap on black friday). I use this subscription along 6 different outlook.com accounts:
1-Personal Cloud (personal documents, pictures, etc);
2-Coding Learning and Tools (I have basic knowledge about web-dev - and I am working to improve it. Plus, I am learning Docker and Python).
3-Fantasy Cartography works (I draw Fantasy Maps for money using Campaign Cartographer 3 and PaintShop Pro 2019);
4-Installation files backups (I also have access to MS Imagine, so I have many GBs of disk images, softwares, etc - you never know when you will need a server or sql image);
5-Wife’s Personal Cloud;
6-Media Library/Backups (music, movies, comics, ebooks, etc).
This setup gives me 6TB storage space for about US$ 65/year, plus Office 365 (which I almost never use) and six hours of skype calls (one hour per account).
Since some of my software won’t run well (not even through a VM) on Linux, I need to keep at least one Windows install all the time (desktop at home and desktop at work), while I run Linux on my laptop. While I have all that data also stored on external drives, all my computers run on 240GB SSDs, and it is a real pain in the butt not being able to access my cloud on Linux through a GUI interface.
So, basically, my use for OneDrive InSync client would be to access all these 6 accounts on my Linux box, especially because is the one I use most - and, well, I would gladly buy the six licenses just for that purpose.