Why does everybody seem to think that userspace attestation is the only use for the TPM? The primary use is for data to be encrypted at rest but decrypted at boot as long as certain flags aren’t tripped. TPM is great for the security of your data if you know how to set it up.
Valve is never going to require TPM attestation to use Steam, that’s just silly. Anti-cheat companies might, but my suggestion there is to just not play games that bundle malware.