What's the catch with GameGain ?

Recently I was about to donate an ancient laptop I had to my 4 year old nephew who showed interest in laptops but rather for playing videos and browsing youtube , so I managed to upgrade it to windows 10 which went up fine despite not even being supported but i did notice it to be quite iffy performance wise . So out of blunt trials before I rest the case I tried an app called GameGain .

I was thinking it would probably end up another fake ware or pc clean up tool or would design a mode that would shut down everything running and dedicate everything to the specific app i choose , to my surprise it did nothing of that it just did some gizmos based on cpu selection and next thing the laptop can do X 2 fps of what it used to do and running smooth as is without even producing any extra heat ...

Now I googled for catches behind this or for what exactly are they applying , I mean if hardware can deliver X 2 performance with only few registry tweaks then why arent manufacturers doing it on their own , however I found little awareness of its existence .

The reason why I opened this thread is that I am highly considering installing this on my other valued laptops but i am wondering if there is a catch really with this thing . I mean i dont wanna lose my work or gaming laptops , so any thoughts ?