Individual attachment sync toggle

MG6

I have a suggestion for consideration. I think letting Zotero file my article PDFs and other attachments for me is the easiest way to ensure they won't be lost on my drive and forgotten forever. The only thing stopping me from letting it take over completely is my limited online storage quota. Forced to choose between file management and sync, my two favorite features, I have been adding only the most important files to Zotero. Someday we may all have our own cloud servers, but until then, would it be possible or desirable to add a toggle to each attachment, just on/off, that controls whether it is synced? I am thinking of something kind of like the check box in a certain jukebox program that stops a song from be added to an MP3 player, only not at the top level of an item.
Thanks!

MG6

PS-- One of the reasons I want it is that it would also make it easier to manually sync Zotero and file libraries on different operating systems. You can just link to a local file, but it's not really possible to mirror paths between Windows and Mac, for example, and they can't launch each others' shortcuts/aliases.