The ULP coprocessor only claims a power consumption of 150 uA (which is huge compared to actual low power devices - EFM32, which is an ARM Cortex M3 MCU, runs on just 1.45 uA)
Combine that with the fact users see real power consumption up at 450 uA [1], you won't be writing a program that lasts more than about 3 weeks on a regular CR2032 coin cell.
That's a 2 year old github bug being fixed, not the actual usage people obtain in the wild.
Here's [1] a commercial ESP32 board that draws 1.5uA, and, as others point out, comes with vastly more hardware at a lower cost [2] than the EFM32 arm core you listed.
This was then resolved (id depends on the use case also), also you are comparing Low Power CPU (ARM Cortex m0-m3), which you need to pair with something probably esp32 to connect it to the internet.
