It's not just compression. These kinds of schemes can e.g. eliminate a massive number of extra roundtrips over a high latency mobile link. Or eliminate most upl

It's not just compression. These kinds of schemes can e.g. eliminate a massive number of extra roundtrips over a high latency mobile link. Or eliminate most uplink traffic completely (basically you'd just need to issue a request for the main page, all the subresources could automatically fetched by the proxy server and pushed to the client without it specifically requesting them). And that can be a huge win on mobile, since uplink tends to be way slower than downlink and often becomes a bottleneck for pages with many small resources.