But it's not necessary to use your private key for decryption.
Really? I believed that for decryption the private key corresponding to this public key should be in the wallet.
Sry,
yes;
after testing using my other wallets, it does require the prv key to decrypt the message.
This can work using an imported wallet with one dedicated private key for exchanging encrypted message.
Although, there's no real advantage over PGP/GPG.