The problem is that this feature mostly targets users who are trying to get rid of lenovo software.
On a laptop you would normally restore your system or reinstall windows using the recovery partition which is full of vendor-added software. If you went through the trouble of installing a clean version of windows (by finding an OEM install of windows you can use your key with) it probably means that you expect your installation to be clean of any lenovo software. But guess what, you still end up with Lenovo software installed behind your back.
I'm not saying there is absolutely no good reason to have the Lenovo software installed, but they could at least prompt you with a message like "We detected that you are running a fresh installation of windows, would you like to install our software to improve the performances of your computer and fix known hardware problems ?". Then it's your choice to go along with their software or handle the possible windows update mess yourself like a responsible geek.