Yes, you do need a file system for that. You can't currently reply to an email and attach more than one PDF or Word document. The mail app doesn't have that capability, and neither does any 3rd party app. How often is that necessary? For a great number of users, several times a day, and yes, from an iOS device. It's foolish to think that because one user doesn't need a particular capability, that other users won't. It's a very basic need shared by millions of users.You don't need a file system for that, especially a user accessible one. You just need a mail app that can locate the files. Which the ios one can, because your word app can send the file to mail. Yes it might be nice if one could do it from mail, select several documents etc but how often is the average user really needing to send several documents of different types from a tablet.
Again, not true. Just because this functionality isn't important and useful to you doesn't mean others don't have different needs. More people would be using this functionality if Apple provided it.Users with that kind of need typical use a computer anyway.
The same applies to you. The difference is, if the capability were present, those who need it can use it, while those who don't need it don't have to use it. So having the capability satisfies all users. Not having it doesn't.Not ideal FOR YOU. But you are not everyone. Your needs and opinions are not universal.
Your "simple" workaround, which isn't so simple, won't accommodate sending more than one file at a time.Exactly and there's a simple work around too: