Someone else may be able to say this better.
The tools cannot just be copied on your computer if built on another.
You would still have to add the path to your environment variables and some will just not work at all.
It is true that sometimes if one file is missing or corrupt it can be copied from another persons build but for copying the whole thing I can't imagine it would work.
For those people, there is the precompiled bitcoin.
This is not the same. I was talking about downloading the build environment and then compiling rather than compiling every library yourself.
The amount of potential errors is outstanding.