https://crypto.stackexchange.com/questions/48423/is-it-bad-to-expose-the-public-key
Cant think of a reason for not giving out your memo.cash pubkey.
But my BCH pubkey for memo.cash is already public and available in these tx. Another rule of crypto: signing/with key is never used encipherment. Ever.
Here's a quick python script to convert that pub key to something you might recognize: https://imgur.com/a/kTr3qkS. So we publish our pub key to the block chain on every tx.
When you expose the pub key, it's a privacy issue. But more importantly, if there's a weakness discovered where the priv key can be found with the pub key, your funds are protected.
A few msgs coming. When you spend money, you have to publish the pub key in the scriptSig of the tx. That's why we have change addresses for EVERY tx: because you expose the pub key.