One of the Google guys, Paul Lewis, said achieving 85 or better should be your goal. Of course those things you mention matter. Both to Google and, especially, users!
Page render blocking is blocking your page. Is it a problem? Maybe not for you but Google is suggesting you look into it and make sure. (Thanks!). Saving 1.8MB of bandwidth? Holy cow! Maybe my images are too big. If not, what is it? Inline styling? What a pain. Are they wrong? No!
Anything that makes your web site load faster is always good for the user! Thanks Google!
But overall, Paul agrees with you.
Now the thing to bear in mind about PSI is that it’s distilling down a
collection of very good (and broad) set of rules and seeing how your
site measures up. It doesn’t really care about context or what you
chose to do or not do as a team. As such I just tend to see PSI as a
checklist of things that are somewhere between “a good idea” and
“crucial”, and I don’t aim for a score of 100 across the board.
The reason I’m not going to pin all my hopes on a PSI score of 100 is
that it may make my development more difficult. Inlining CSS and
more context is required here.
And even Google will say that.
A higher score is better and a score of 85 or above indicates that the
page is performing well.