Espressif themselves do this for their own prerogatives. The ESP32-S3 MCU from this story actually has a small, low power RISC-V core that deals with several things, including "deep sleep" tasks. Many ESP32-S3 users are unaware that their dual core Xtensa device also includes a RISC-V core; it's just there, transparently doing Expressif stuff on a dedicated core, immune to whatever is going on with the fast cores.