It's always the SAFEST course of action to never touch the official category structure. However, it's NOT always the BEST approach to avoid touching it.
When the changes you want to make are purely additive, and you can simply disable aspects you don't like, editing the official structure is potentially the better option. That way, if you choose to import content that users the official structure, everything folds into the SAME categories. All that differs is that the content you've imported will be missing your extensions and may contain aspects that you've hidden for your own purposes. The net result is vastly easier to integrate into your realm compared to having topics based on a completely different set of categories.
The big question here is what the Village Backdrop template actually looks like. Thankfully, they have a free PDF that I could take a quick look at, so kudos to Raging Swan Press for making my life easier in answering your question here!
Looking at the Village Backdrop structure, there are an initial set of paragraphs with some general description, background, and history details. Then there are groupings for Demographics, Notable Folk, Notable Locations, Marketplace, Village Lore, Villagers, and Whispers & Rumors.
This doesn't seem drastically different from the Community category structure used within Realm Works. The category structure consists of: Overview, Description, Notable NPCs, Profile, Story, Points of Interest, Valuables, Internal Relationships, Outward Relationships, Background, and Additional Details.
From my quick inspection, there is an almost direct mapping from Demographics to Description, Notable Folk to Notable NPCs, Notable Locations to Points of Interest, Marketplace to Valuables, Village Lore to Story, Villagers to Profile, and Whispers & Rumors to Story. Consequently, you could very readily use the official category structure and drop into place all the pertinent details from a Village Backdrop with negligible need to carve up the material differently.
The impulse might be that the paragraphs of description to start each village entry would need to be assessed and mapped into the appropriate sections of the official category structure. However, you could completely ignore that. If you just dumped all that material into the Overview or Description sections, you'd be fine. Carving it up differently would be an entirely optional thing.
If you prefer the names used in the Village Backdrop template, you could rename various sections of the official category according. As long as you're not changing the underlying meaning of anything, using alternate names you prefer is perfectly safe. So you could rename the Valuables section type of the category to Marketplace, or Points of Interest to Notable Locations, or Notable NPCs to Notable Folk. Those changes won't impact anything, but they may be more suitable to how you think of things, so go ahead an make them.
You could also add your own new section type for Whispers & Rumors. The official structure puts those under the Story section, but you can split them off into their own if you like. When you create your own communities, you'll get that section auto-created to fill in as you see fit. If you import content from others, it will typically have that material under the Story section. That's not a big deal. And you can easily edit any content you import to break that stuff out into the separate section. Simply use the "Synchronize Structure to Match the Category Definition" on an imported topic to get any missing sections you've added to appear. Then drag-and-drop the desired snippets between sections. Now the imported content matches your structure with a few quick steps.
The bottom line is that it's absolutely NOT a black-and-white decision, as the original question frames things and some seem to have advised here. As others have said above, there is no "right" answer here. It's all subjective, and the ultimate goal is for you to settle on something that works optimally for YOU. Given the substantial overlap and similarities between the Village Backdrop template and the official Community category structure, you'd probably be best served by a hybrid solution that retains much of the Village Backdrop approach (through renaming and adding a section or two) and also leverages the original category structure.
Hope this helps!!!