[WildCard65]

I have to go with NOT using a json api for the SM plugin on the account that sourcebans I believe should be independent of 3rd party extensions, your current plan would make users have to install SMJansson + either 2 extensions: CURL or SteamWorks.
The original sourcebans only required the MySQL extension which is STOCK of SM.
On the otherhand, the JSON api would be useful for community webpages + forum plugins.

In conclusion: I say do keep the JSON api, But don't make the sourcebans SM plugin require that api especially since it'll cause more overhead then interacting straight with the database would create