They would care if they knew it would also block their program doing the output...
Compression yes
It can pipe many megabytes of text output per second on relatively slow channels (`ssh -vv` prints the total data transfer when you close the connection), as long as it's not encrypted or unable to be compressed for some other reason (which is pretty rare for text output).
Scrolling very large files in vim becomes much faster, for example.
It is great for unstable / slow links and pressing ctrl+c works immediately which is nice.