Hardware key storage is a low level security primitive. Both Android and iOS have mandated it for far longer. It's a low level security primitive that enables a lot of scenarios, not just DRM.
For example - it's not possible to protect SSH keys from malware that achieves root without hardware storage. Only hardware storage can offer the "Unplug It" guarantee - that unplugging a compromised machine ends the compromise.
And if you want to play sound, you buy a sound card. Computers integrate components that approximately everybody needs. Hardware storage for keys is just the latest example
For example - it's not possible to protect SSH keys from malware that achieves root without hardware storage. Only hardware storage can offer the "Unplug It" guarantee - that unplugging a compromised machine ends the compromise.