I believe some of those projects having the same use cases come as a way of filling a gap left by the previous project which had the same use case. for instance we have so many projects coming up with different crypto wallets , this is not bad in my opinion because we need a lot of wallets to choose the best . And when there is competition developers who are serious will sit up and improve on their project.
Each project has their own wallets made if they don't rely on Ethereum network as an ERC20 token so they have to make their own wallet. That's why we see projects have different wallet addresses while for the others, we see requiring Ethereum address because they're on the Ethereum blockchain. And for the use case, nothing unique for most of them.