Counting any kind of "internal write effects" that result from a user write (i.e. write amplification) is obviously done to mislead in the benchmark and does not make it comparable to key-value stores.
12k writes/s is the number of rows that are written from a user perspective. So 12k/s is also the number you have to use when comparing it to key value stores. But of course, comparing Fauna with eventually consistent systems is not a really fair comparison. You don't make it fairer by misleading in your benchmark though.
Also, just because some other vendor posted a misleading benchmark on hn (I don't know if they did) that doesn't make it right or means you should do it. Just call them out on it too.