There are no truly 0 sat outputs on the main network. You can probably execute a completely valid 0 sat transaction output in matterpool's SPV network. These transactions could ultimately be settled at a later time or with a batch. Similarly you could use planaria software to capture valid 0 output. It all requires a delalyed settlement if you want it on the BSV chain itself. You actually cannot send a completely 0 sat transaction and have the mining network do anything with it. They'd have to add a minimum 1 satoshi output to this transaction to spend it or "etch" it on the network for you. So when they say you can do a free transaction, it's like the penny at the countertop in an old gas station. It's not a handout, but it's enough to ensure service. Basically to put the sha and timestamp on the actual chain, miners have these penny jars available for special cases. This is how they fix dusting issues on BTC and BCH. We won't encounter dusting issues until trillions of transactions are included in the spend history of a coin. Now, TAAL has a STAS technology in development that allows them to issue a dollar value or any property value (car title, loan agreement, real estate property, land, etc) and these satoshis that are agreed upon by relevant participants to have these values can be sent on the network at no fee because they are already satoshis. They are just special satoshis that people are treating as issued money or capital.