I'm not at all impressed with the loss in quality vs the original.
My current image strategy is quality over file size and page load speed because...
1) Virtually all my clients are served by either 4G or high-speed internet (100 mbps is actually considered kinda slow in homes here), and the difference between loading a 200k, 100k, or 20k image with such high speed service is almost imperceptible (unless there are dozens of images on the page.)
2) lazy loading
3) 5G will be here sooner than these new compressed image formats gain universal adoption in browsers and widespread interest among developers, rendering the entire issue of image size moot.
Since Google released their Page Speed Insights tool, and announced that loading speed would be a ranking metric, everyone has gotten all hot and bothered over getting good mobile scores. The thing is, Page Speed Insight's mobile score is based on an emulated 3G network mobile network, while most of the developed world is on already on 4G. Furthermore, their tool often makes no logical sense. You can do a test where a page loads in say, 5.5 seconds and they'll advise you that you could save 9 seconds by loading images in next-gen formats. HUH??? So the site would time travel to load before you visit it? And, you can test the same site four times in an hour and get four different scores.
Lastly, I have never had a problem getting my client's websites to outrank my competitors regardless of what images I've used, so page load, if it really does factor into SERP ranking, is pretty minor. Most of my sites rank on Page Speed Insights in the 50-75 range on mobile, and 90 and above on desktop. I have RARELY found a Wordpress site that loads faster than 40, and Wix sites are usually in the 10-20 range. And this is what the web is FILLED with.
The main concern is, does your site load fast enough to not cause people to bounce? It is getting traffic, and converting visitors to customers? That's it. If my site's are getting the job done, why should I care about saving a half second to load three different images to accommodate three different screen resolutions, or connection speeds. It's all overkill and it won't even matter in a few years.
Decades ago, when a 20 meg hard drive cost $1000, I used to have a program installed on my Amiga that literally compressed and decompressed every single file written to the drive simply to maximize the storage space. Does ANYONE care about storage space anymore? You can get a five TERRABYTE drive for a hundred bucks!
It's only a matter of time before the issues of image compression, accelerated mobile pages (AMP), website page size, bandwidth and data rate will be just as irrelevant as storage. This stuff matters to Google because it costs them money, so they want to make us believe it's crucial that we have the smallest, most compressed, most efficient, fastest loading websites, or we're all going to lose page rank, and traffic and clients, and it's all bullcrap.