Google minifies HTML on basically all its properties. It's probably about a 50% savings in bytes, which translates to (on my Comcast connection) about 250ms in network latency saved. Multiply out by rough estimates on queries/day and it saves a human lifetime every 2 days.
Repeated experiments - by Google, Amazon, and many smaller websites - have shown that lower latency directly translates to higher conversion rates, so I wouldn't be surprised if this results in billions of dollars of extra commerce, and even a small website would get noticeably higher revenue if they did this. Google also ranks faster websites higher, and so you get an SEO benefit as well.
Chrome DevTools timeline inspector. Loaded www.google.com/search?q=foo on Network tab, clicked into details, selected Timing tab, and took only the Receiving time, skipping the Waiting portion.
It's a little inaccurate because Google Search uses chunked encoding, and so it sends the header immediately, even before the search has finished, then blocks as the search request comes back. Plus there are usually inline images at the end of the response, but I chose my query to avoid them. It should still be pretty close to the general ballpark.
Repeated experiments - by Google, Amazon, and many smaller websites - have shown that lower latency directly translates to higher conversion rates, so I wouldn't be surprised if this results in billions of dollars of extra commerce, and even a small website would get noticeably higher revenue if they did this. Google also ranks faster websites higher, and so you get an SEO benefit as well.