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.
Sure it won't last long if you use pause and you are connected to wifi. You have boards with a power management chip that allows you to do even more smarter things, for example https://www.hackster.io/news/smart-bee-designs-bee-s3-is-a-1...