For anyone concerned with the speed of their site (that’s a rhethoric question), contact forms can be daunting. Take the widely used Contact Form 7 for example: it will load some script and css files on every single page of your website, no matter if you have a form on it or not.
Here is a screenshot of a website without a form, but CF7 installed:
And here you see the same site, with CF7 deactivated:
So you have a couple of extra requests, and some extra data loaded, slowing down the page speed without any benefit at all. In this case, almost two seconds, if you compare the “Time to interactive” measurement!
Ideally, the scripts required to run your forms will only be loaded when there is a form on the page. That will increase the performance of your WordPress website and thus, make it way more user friendly.
And, of course, Google will appreciate your efforts, too.