The PageSpeed grade or GTMetrix score are not indicators of speed. Neither your real visitors, nor Google will never see your website’s “grade”.
Speed is the only metric that matters for SEO, user experience UX and conversions.
Yoast, the expert on all things related to SEO for WordPress states:
Google just looks at how fast your website loads (perception of complete Above-the-fold content load) for real human users, so you don’t have to obsess over that specific score. You have to make sure your website is as fast as it can possibly get.
PageSpeed Insight tool can be best explained as Web Development’s Best Practices tool.
The simple truth is this:
Perceived performance is the measure of how fast a user feels your website is loaded and ready for their usage not necessarily how fast your technical stats (Grade) say it is. This is what counts for user experience and for SEO.
If you try to attain a perfect grade A(100%), by implementing all the suggestions Google PageSpeed makes, you will lose your sanity pretty quickly.
Think back to your school days. Did perfect grades mean you were smart? Not necessarily. It just meant that you knew how to do well on tests.
So just like school grades are not an indicator of intelligence, Google’s PageSpeed grade alone is not actually an indicator of speed.
You cannot take too literally all of the suggestions from Google PageSpeed because sometimes they are unrealistic or impossible.
For example, it may tell you to minify or add expire headers to a file that is not hosted on your website. This is impossible.
Google PageSpeed can be helpful as long as you don’t treat it as the be-all, end-all.
At the core, speed optimization is all about improving user experience.
It’s a perfect balance between seeing sharp & crisp website but FAST!
Users appreciate fast loading website but they don’t like to see blur images either.
When optimizing website keep in mind how your user would feel, what do they want.
Follow your users, they are always unsatisfied and they always want more!