If you are wondering if the WordPress plugin named jetpack will slow down your website or not, you are right to assume that it will 👍 At least it does in my case. As I tested, our website loads quickly without Jetpack. With jetpack, it showed significant delay in load time.
Jetpack is good with a lot of features such as stats, backup, security suggestions etc. But we can't sacrifice our website visitors for the sake of more features. If a user waits too long for the site to load, there is a good chance they will leave the site
So i suggest you test your website load time with and without Jetpack and see the difference. Perhaps it might not slow down every website, but it does mine and i have removed it from my plugins list
For stats, I use another lightweight plugin, because previously I used jetpack mainly for stats.
Let us know if you see any improvement in your website with and without Jetpac in comments below 👇