(Just found "Ideas" area, apologies for double post)
We use online Office apps a lot for collaboration, and share links via email. When I share an Office file stored in Sharepoint, all I do is insert the link, and no instructions are required. The link opens the doc right in O365 for viewing/editing. Right now, when I share a link to an Office file stored in Egnyte, I have to send instructions with the link, for example:
"Click this link: xyz. A preview window will appear. Click 'Go to folder' button on the right side of window. The folder containing the file will open in Egnyte. Right-click the filename and select Open In... > Edit in Excel Online"
This has resulted in us just not using Egnyte for collaboration with Office files and going back to Sharepoint, as the overhead for explanation and use is too high.
A per-file option to open directly in O365 online would work, or perhaps better would be an option when creating links to Office docs "O365 only" that creates a special type of link that opens directly in O365 without all the fuss.