It is a IoT thingy with wireless connection which puts it in category where certain factors combine. * Cost effective solution for lightbulb would be not havin

It is a IoT thingy with wireless connection which puts it in category where certain factors combine. * Cost effective solution for lightbulb would be not having it wireless connection at all instead of having less powerful MCU. So it being IoT already means that target audience doesn't care about the price that much. * It uses of the shelf FCC certfied wireless module with embedded antenna. For product designer it makes sense using a ready module because it avoids need to do RF design and the certification.It also simplifies the design if you run your user application inside the wireless module instead of having an additional MCU communicating with wireless module. Such modules tend to have medium to high end MCUs. Why do wireless modules need such processing power? * 2.4 Ghz Antenna has certain size requirements so the size constraints for rest of the system aren't too tight. * Wireless circuitry puts the module in certain price category, it makes sense to have the MCU in similar price category. Wireless certification is a pain, so there will be less product variants for wireless modules compared to something like 8bit micro controller which come in wide variety of memory, size and IO configurations. If you have single product variant better have slightly more powerful MCU part making it suitable for wider range of applications. * The wireless communication part itself has certain amount of memory and computing requirements. Might as well split the resource budget on the same order of magnitude for wireless part and user application. N kB of memory for wireless and N kB for user application instead of N and 0.001N especially if the first part can easily vary by 10% or more due to bugfixes and compiler changes. Similarly there are basic speed requirements for digital logic buffering the bits from the analog RF part and doing the checksums. * Modern silicon manufacturing technologies allow easily running at few tens of MHz so if the SOC has memory in the range of 30-500KB and isn't targeting ultra low power category it is probably capable of running at that speed.