I think this has a lot to do with whether you use Genesis extensively and have a lot of products that have metadata with them by default. I find it’s much easier using these products via Smart Content than from the DAZ Formats Content Library folder, which is even more confusing for me than the Poser Formats library. This gets you using SC and you start to see the benefits. Otherwise you aren’t going to see the point of it. By adding metadata to the rest of your stuff you will then only have one place to go for content instead of two or possibly three. I think it is newer users who are going to be more motivated to understand and use SC for this reason.
I’ve only fairly recently started using Smart Content for “runtime” stuff and I had up until that point extensively reorganized my runtime, but I now find SC more convenient. I’m also probably weird in quite enjoying adding metadata—I find it quite fun!
Me too! I think the enjoyment has to do with stimulating different parts of the brain. I’m at my happiest when I’ve got several things happening at once, and usually something technical like coding, something artsy like a Reality render, and something organizationy like my Smart Content and metadata. I find it very satisfying to have my stuff properly organized, and working with product thumbnails rather than files adds a tremendously pleasant aesthetic. I used to play Napoleonic wargames as a kid and I got a kick out of having my guns, dragoons and hussars all nicely lined up before battle
Please tell me if you think this is off-topic and I’ll edit it to say something sensible (and a little less embarrassing).
Well, I created my very first “metadata”. As one of the key .pdf files got damaged somehow in transferring between my online and offline computers; it was partly following one of the instruction .pdf files and partly guess work. End result, well it works on my computer and I’ll guess it might on somebody else’s 
Notes I made ‘til about page 7…
tips for adding new items to Smart Content:
For the “Scan for New Files”, UNCHECK the “only new items”.
In discovering “how to” “where to” it could be that one puts a reference where it is not wanted. So yes one can ‘remove/delete REFERENCE’ ... and after removing all the references one may discover that no matter how many times the search for content is repeated one’s product is simply not going to reappear in the “Unassigned” section.
Brainwave Strikes Again! 
Close D/S4 and open the real folders, slide to the Desktop the actual folder containing the desired product.
Open D/S4 and run the search for products gizmo.
Close D/S4.
Open the real folders and slide back into its place, the desired product waiting on the Desktop.
Open D/S4 and run the search again checking to look for ‘new’ ... and there it’ll be! [was trying to get it to show up in the unassigned once more]
If I set up other categories are they only on my computer or will they also appear in other 4.0 programs in which this product is installed?
[we were told that Napoleon had cold hands and that’s why in his portraits he often had one hidden]
