Does page weight matter if your Core Web Vitals scores are good?

At my company, we’ve done an excellent job showing people the value of using user-based metrics like the Core Web Vitals for performance testing. But this has also become a bit of a two-edged sword.

According to the Google Search Console, mPulse, CrUX etc, we have excellent CWV scores.

My concern is that the page weight of our homepage and other CMS content heavy pages is around 5mb, on the small end. Sometimes if they go crazy with videos and haven’t been paying attention, they can balloon up into the 15mb range.

From a user’s standpoint (and thus, from my standpoint as the performance guru), if all that weight is lazy loaded and the page appears fast, does it really matter?

Nope (at least from my experience). Make sure the user experience is good on slow connections as well but as long as you’re not dropping users from your stats because of sampling bias (slow users abandoning), excellent work!

Bonus points if the videos are adaptive to bitrate and are only 15+MB on a fast connection.

There’s some potential issues with metered connections and bandwidth caps for some users so don’t go too crazy but from a pure performance perspective, measured size doesn’t really matter as long as you can deliver the experience you want to, quickly and smoothly.