I use them mainly to check
my SIV utility works on all versions of Windows from NT 4.00 (it's half OK on NT 3.51) up to the latest Windows 11 x64 Enterprise V10.00 Build 22593 which I run on my ASUS Maximus Z690 Hero. Another consideration I can't sensibly use my main development system to test my drivers, some of my systems are setup to make testing easy for me such as my Dual P-3 with 5 GPUs!
Back in the day I never really had the time to implement all the support I wished to, but now I am retired I am retrospectively adding this. When adding support for GPUs that can't be reported using NVidia's NVAPI, AMD's ATIADL or Intel's oneAPI I like to compare what SIV reports with other utilities, hence I tried GPUZ. As W1zzard highlighted doing this without appropriate test systems is tricky.