First : Both cryptopia and nova exchange are not web wallet and you shouldn't trust any of such exchange with your coins. Both of them are also comparatively small trading platform.

Second : Web wallets and exchanges are not true bitcoin wallet so you shouldn't trust them with blind eyes.

If you are looking for multicoin wallet than use exodus, jaxx and if you want SPV wallets for bitcoin only than electrum is best as hot wallet. For cold storage use ledger, trezor like hardware wallet.