Yes salary payouts where the world knows who you're employed by are a good use case for Paynyms, because the world can see the notification transaction from employer to you (unless you exchanged codes out of band, which I doubtc or unless your employer uses solid privacy techniques too), but can't identify the actual payout transactions.

Donations are not a good use case for paynyms if the sender does not want to reveal who they are donating to. Even though you cannot see on chain how much the donor gives and the donation transaction, the notification tx goes on chain linking donor to donee on chain, again requiring the donor to use other privacy techniques (not Paynyms) to sever the link.