Why are ZoneInterface validator functions readonly?

[valerioleo]

As I experiment more with Seaport and Zones, I tried to create a dummy smart contract that registers some data about a trade (e.g. which tokenIds are left to sell). Ideally, I would have done something like:

User -> Seaport -> Zone (flag tokenId as sold)

but the above is not possible because Seaport calls to the Zone are readonly, so I need to do

User -> Zone (store here data) -> Seaport (calling the `matchOrders()`)

The disadvantage is that now user interacts directly with the Zone instead of Seaport, which I would like to avoid.

Has anyone worked with a similar problem? Is there a way to make write-full calls to the Zone from Seaport? If not, what informed the design of Zones to be readonly?

Thanks for any feedback!