In lieu of the bullshit replies you have gotten, I will answer.
TPM is a security measure. By default your hard drive on Windows 11 will be protected with bit locker. Bit locker is hard drive encryption. It does more stuff but that’s the broad strokes. This means that if your laptops get stolen or your computer gets stolen or whatever it is no longer in danger of all of your information and files being taken.
There are other advantages as well. For example a TPM could make it much easier for anti-cheat to detect cheating. However, no games use it yet because not every system has a TPM, blah blah blah.
TPM is actually a really good thing. The problem is that the vast majority of systems do not have a TPM header and therefore cannot add a TPM. This means that those systems have to be replaced.
I work for a managed service provider so I deal with a lot of companies that refuse to upgrade their systems. Thanks to Windows 11 they are being forced to upgrade systems that are up to 15 years old and basically unusable. This is actually kind of a godsend. There are downsides to this yes, but it is not just some ill thought out idea.