Message in SEO Assistant

I am trying out the new SEO Assistant en the SEO Assistant say this:
Why is this and am I not allowed to have animation on my site?
What is then the purpose of it?
Or am I looking at it the wrong way?

Screen Shot 2020-11-15 at 08.50.10

Oh you are allowed. It’s just that any tool that looks at page load timing will look at, say, a fade in animation and say, “this page is loading slowly”. And give the page a worse score.

From a SEO point of view it’s best to make the top of the page rock solid and non animating.