[stolk]

It is a SoC with MMU. It just looks like a MCU.

64MByte RAM, (45MByte of it free after logging in.)

[monocasa]

It also has MCU cores in addition to the application core.

In fact I don't think there's anything stopping you from just running on the larger MCU cores and simply disabling the large core if you really wanted to for some reason.