The Haskell Testnet is a testnet made to simulate the future Shelley network, on a testnet.
It's important to note that the Haskell Testnet, has no link with the Shelley Incentivized Testnet. Stakepool nodes are based on Rust, while Haskell nodes are, obviously based on Haskell. If you currently want to create a stakepool, creating a Haskell node will have no benefit for you. And if you want to create a Haskell node, creating a stakepool will have no benefit for you.
If you want to create a Haskell node, you can follow our guide here 👇