HARA needs to be implemented by using a proven technology that's why the decision to use Ethereum was made. Also, Ethereum has the biggest dApps projects connection support to other layers through Oraclize, Infura, and so forth. It also has the most robust community and developer support. HARA is not closing its doors to other blockchain tech, that's why HARA is also exploring reasearch and development partnerships with other blockchain tech companies.
Is there any plan to build your own blockchain? Or are you looking for interoperability solution like Cosmos/Tendermint or Polkadot? I'm not sure how will all of this play out when you already release the tokens and it's used by the ecosystem. I'm saying that for some new users, token swap might be difficult. Not sure how farmers will react to that too. So it's better to decide from the beginning whether you'll build your own blockchain and keeping interoperability for others blockchain to ensure there's no need to do a difficult token swap or something like that.