WiFi is a difficult protocol, so it makes sense to use a radio coprocessor. The ESP8266 can also have trouble running non-trivial applications while reliably handling WiFi, and in 2020 a Cortex-M0 chip is probably at least as cost effective as an 8-bit micro.

They don't need those chips to make your coffee, they need them to connect to the internet and to avoid hiring expensive experts. 5 years from now this might use a single ESP32-S2, but it doesn't seem outrageous, especially when the machine also has a display.

Plus, as a bonus, you can use it to mine Monero! Small correction to the article, STM32F0s have a PLL so they aren't limited to the crystal's 8MHz frequency. They're rated for 48MHz, but you can also overclock them.

Smells like someone is already brewing up a Doom install.

It's simply cheaper that way.

A standard, more powerful part is usually much cheaper than having to do more customization, and these CPUs are so cheap that making it cheaper simply doesn't matter anymore.

For projects made in small quantities, as soon as you need a touch display, throwing an Android phone at the problem is often the right solution, even if you just need something extremely trivial. Sure, I could do it with an 8-bit microcontroller and physical buttons, but by the time I've designed a custom board for it, the time I spent was worth more than the phone.

I just see technology is to the point that processors of this nature are so common we can waste them in coffee makers.

we have coffee makers more powerful than the first computer's I used in school!

No.

They sell you 32 bit CPUs to make your coffee. It's more profitable that way. You don't need any IoT nonsense to make coffee.