I know Daz has plenty of in-house add-ons but most of Itch's are honestly way cheaper (Why the heck is a pack of dogs 100 bucks???). There's not a tag for Daz when searching so is it just a way more niche tool (For non-NSFW purposes anyway) than I thought?

It's a very different market. Daz - and I assume you mean Daz Studio or Daz 3D is mostly used to create 2D representations of 3D assets either professionally or as a hobby.

Assets here are meant to be used in games and many of them are low resolution (would look rubbish in a high-quality 2D render) but work fine when your character is running past them in a game.

To import the assets into Daz would be a mission. You'd have to import them multiple times trying different sizes until you got the scale right. Then you'd have to re-apply all the textures manually, and setup the Iray settings (e.g. if you wanted something metallic). The assets would also not be rigged in Daz - i.e. there would be no animation of movement of limbs. You would basically have a static prop - that's all.

Pricing: Daz does not operate a free-market system. They strictly control the prices to cover their overheads, marketing, price of testing and packaging the product, and paying their published artists. They do not accept products unless they feel they will recover all their costs from the products. 

In contrast, Itch.io accepts everyone and everything (subject to certain payment and legal restrictions). They have no physical quality control (in terms of checking the actual product) and allows users to charge what they want. Most users have to do their own marketing - there isn't a ready audience because of over-supply.

Since you mentioned dogs, I had a look at 3d dogs here and noticed a pack that has a reverse sale (more expensive than usual). Comparing those dogs to ones you'd buy at Daz:

1. The ears, mouths, and eyes can't move.
2. The bodies are a single colour and some look like plastic. You might not be able to easily retexture it to look furry because it will depend on how the dog is UV mapped.
3. Their feet are not defined - no toes or nails.
4. You would have to rig them yourself to get any animation or expression outside of blender.
5. But if you need a dog for a 3D game - they're awesome. 

In contrast at Daz:

1. The eyes can move.
2. The textures look soft and furry.
3. The dogs are animated - mouths can open, eyes and ears can move, they can have expressions.
4.  Their feet are defined with toes and toenails.
5. They will work out the box in Daz - or you get your money back.
6. They probably won't work well in 3D games - too high resolution. But would make stunning 2D renders that can be used in games.

Also be aware that some assets are packaged for specific game development packages. For example, an asset pack packaged for Unity could probably be imported into Daz but you would need to first import them into Unity to "unpack" the assets, and then find them on your hard drive, and reimport them into Daz.