Why does Google PageSpeed ​​show different numbers than what I actually see?

Question

Web development

Hello.

Understanding site speed.
Through Google PageSpeed ​​Insights I see that the download "For computers" is 71, and "For mobile" is 12
Why can there be such a big difference?
Google advises:

Minimize work on the main thread - 7.1 sec.
Reduce the execution time of JavaScript code - 3.7 seconds.

But these problems are not on the desktop.
The second issue is that if I load the page myself in Chrome, the network tab is set to:

Finish:
6.74s DOMContentLoaded: 2.37s
Load: 3.77s

And in PageSpeed:

Loading time of the first content - 6.2 sec.
Load time for interaction - 12.6 sec.

Explain, please, in what here there can be a business.

Answer 1

It is quite obvious that Pagespeed is running tests on a weaker machine than yours.

Answer 2

Explain, please, in what here there can be a business.

in the distance
you check on 3-5 sites in different locations

Answer 3

try gtmetrix.com where you can choose the location