@jonatandor35
If you are talking about the Wix welcome page, then yes I’ve used it myself.
I would say honestly that it does make the mobile site load a bit more slowly the first time that you go to it when you have the welcome screen load up first.
However, the benefits are that the user is seeing something visual on their mobile device and so they know that the website is running and depending on what mobile device you are using, the actual extra time is nominal if you are on a newer and better device, with obviously older devices being slower.
I did use other preloaders too with moving gifs, however the client didn’t like that option and prefered the Wix version.
I used it as a lot of the users for that site it is used on will be the older generation and probably won’t be spending the money on new mobile devices and so for them the website will appear slower on their older devices.
So this gives them a visual indication that the website is up and running as some have thought that when I had used a simple spinning loading circle, that the website wasn’t working and would try reloading again etc.