Great! I do find that PageSpeed/Lighthouse are nothing more than a good indication, but it’s always nice to see that.
About their problems:
- their speed indexed are probably US-biased, if your visitor base is say in Australia, I doubt they measure speed from an Australian point of view, and yet you need to have your servers there, or it will be slow to your main audience!
- they seem to measure the “fold” (where the browser window typically clips the page) at an arbitrary position that’s not documented anywhere I have found, and then will flag a perfectly reasonable page because of that;
- they warn for image size that is sometimes really a few bytes here and there, or excess metadata, but not for image compression level that could be much more aggressive without a perceptual change (yes I have gone really deep on figuring this out for the next Sparkle)
- their accessibility measurements are bogus, they appear to measure the wrong thing (double checked with the WCAG color contrast checkers)