Preload, PreConnect and Prefetch really helpful to improve speed of website?

[Kanika thakran]

Hello all,

I came to know that few  resource hint directives like Preload, PreConnect and  Prefetch are really makes role to improve speed for your website.  Is this right?    Can you show any popular website which has used this tags?

Source-  https://css-tricks.com/prefetching-preloading-prebrowsing/