"Unfortunately, we do multiple operations on Bigtable in one request to our api and we rely on strong consistency between those operations."

I feel like "strong consistency" is misused here. Strongly consistent is relevant only in a distributed environment. Its usually solved by using paxos/raft between the replicas. Bigtable only has had best-effort replication, so I am not sure its being mentioned here. I think they are looking for the term serial, that their queries have to be executed in a specific order for a particular user request.