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.