I don't think this is really very true anymore, and I say that as someone who moved away from using an iPad as my main portable. I'm sure there are specific cases where that's still a problem, but now that it has a file manager, USB drive support, a full array of cloud services support, etc. etc., this is just not a big deal.

At any rate, if you're a dedicated Microsoft Office 365 user, you can be working on the iPadOS version of Excel and using the same files stored in the same cloud service (ideally OneDrive, of course, from Microsoft's point of view) pretty transparently.