My first reaction to this was nervousness. Of all the companies to trust with intercepting and rerouting page requests, Google aren’t exactly squeeky clean, what with that whole surveillance business model of theirs.
Still, this ultimately seems to be a move to improve the end user experience, and I’m glad to see this clarification:
Lite pages are only triggered for extremely slow sites, so we encourage developers to measure how well their pages are currently performing over slow networks.
Lite pages as a badge of shame (much like AMP in my eyes).