If you care about network bandwidth you can compress before sending, as virtually all web applications do. Then you don't need to worry much about the space efficiency of the application format.

Of the wire format you mean? I compress it and still need to care about the space efficiency of the wire format beyond that. Compression ratio does improve a lot when not doing our own, end result is significantly larger. Also it becomes also significantly slower because more data to process which is possibly the bigger problem.

It's probably not like most web application, it's hardware data loggers that produce about hundreds of millions to billions of events per second (each with minimum about 4 bytes of wire format and maximum roughly 500 bytes).