I asked the same exact question for other stuff too that I find super loco. e.g. Why would anyone ever get NVIDIA's, etc. drivers anywhere other than NVIDIA's OFFICIAL site? Why would anyone use any 3rd-party tools (DDU, etc.) to remove drivers rather than the vendors removal tools or system (Windows, etc.) baked-in tools? On and on.
But, many users make-up these very lame shilled/uninformed excuses (mainly due to others persuasions or because an old issue that happened moons ago or they just lack the talent and they need a quick so-called remedy) for today's issues. But, these same users that are utilizing these 3rd-party sources/apps are also wondering at times, why do they continue to have so many performance issues, etc.
WELP!
You kinda bent it in your favor there.
1. Drivers I can understand, but there are tools like Snappy Driver Installer(and DriverPack Solution in the past, when it used to
not install bloatware) that make life many times easier for people who, say for example, perform windows installs for people on a very frequent basis, like 4-5 times per day. Of course said tools would also have their own
official sources to download them from, after that everything else is a risk.
2. 3rd party tools are often much more functional and thorough than the baked-in alternatives.
- the DDU example is massively wrong - I use it in my line of work very often to fix people's mess when they've downloaded and installed driver upon driver upon driver and wondered(like you said) why they have many performance(or other) issues. So far I've only once or twice used it to clean up Realtek HD Audio driver, it did the job. But for graphics drivers it's a must, this tool. Clean windows 10/11 install or just installing new driver/cleaning leftovers from old drivers.
- my own example would be abbodi1406's Visual C++ and DirectX repacks - both are a fraction of the total size of the official download(~30MB each repack vs ~100MB for directx alone and maybe the same if not more for multiple separate vc++ installers, all of which have a bunch of installer payload you don't really need), perform a cleanup before installing anything, have switches you can use to perform specific tasks. All this made by a trusted person on a well-known trusted forum(I'm sure some here have an idea)
There are probably many positive examples to be given, I just haven't experienced the need to use some of the stuff that exists out there. After that come things like crappy bloatware/shady/malicious websites that use the name of an otherwise useful piece of software to rack up clicks and spread unwanted/harmful crap.
TL/DR: Don't lump everything under the same lame mentality of only using what the manufacturer provides. I use non-oem aluminum window hangers on my Golf Mk4 because the oem plastic ones break whenever they feel like it. People use cheap "aliexpress/ebay turbos" because buying a proper built turbo from a reputable manufacturer costs "too much" and is "unnecessary". Those are two completely different approaches to solving problems. Same with software.