Grin blockchain system demand from wallets to receive tokens to be in listen mode with an open port to your system and to expose your ip.
There and a much worst grin wallet from grin the wallet713 that your transaction relay from central servers....
Grin certainly does not demand to send tokens via http and the method is altogether discouraged, it is only there for user convenience. The default method is via file exchange where you can choose yourself how to exchange files (also does not require anyone to be online or listening). You can also do the exchange via the keybase plugin and anyone is free to implement plugins for any communication method they like (Signal, email etc) via the exposed wallet interface.