PC gamers are notorious for tweaking settings, formatting drives, and reinstalling Windows. For someone who formats their PC frequently, having a lightweight offline installer on a backup hard drive saves hours of redownloading the same files repeatedly.
Yes, a highly compressed BlueStacks offline installer exists and is useful, but you must prioritize safety over convenience.
If you want the benefits of compression without trusting shady websites, do it yourself using 7-Zip.