Big, big +1 for this. The lack of synced shortcuts across platforms is huge miss for Firefox. It may not seem like much but, honestly, having to recreate pinned shortcuts is a pain when most everything else of use syncs.
Need this too. Earlier I had 2 places where FF was needed / used. So I added shortcuts on home page manually. Now I have 5 places. Manually adding / editing is no more an option for me.
Do not know what is holding Mozilla from adding this feature.
There are already many items that FF syncs.
Bookmarks, History, Open Tabs, Passwords, Payment methods, Add-ons, Settings.
It's a shame that there are shortcuts on the main page instead of bookmarks. But if I'm already spending time pinning shortcuts, why don't they sync between devices? This is such a basic thing that is central to all users when using a browser