Folders work standalone, tags don't. Tags don't work without a search feature - we might tag religiously but others don't and won't. If you're implementing a

Folders work standalone, tags don't. Tags don't work without a search feature - we might tag religiously but others don't and won't. If you're implementing a search feature then you no longer need tags. It won't take off. Especially as these days we seem to be moving away from files full stop.