Using PF for non-content purposes has been approved by GMs explicitly in the past, as has ERP.
PF entries for ERP for gil, even.
https://cdn.discordapp.com/attachmen...540/GM-eRP.png
"Gm Dorxenore >> Players are free to ERP if they so choose to. They can also place Party Finder comments to advertise the selling of ERP for gil as it is not a violation."
The GM in OP's post appears to be going against precedent. There's certainly nothing in the TOS that supports their interpretation. Squenix is free to change their minds on that, but they need to update the TOS to reflect that.