The MSP430 microcontroller series has a few features that make it popular in intermittent/batteryless applications:

• Widely used in both batteryless and standard applications, which makes finding tools and support relatively easy
• Low power draw with configurable low power modes, important in the low power environments of most intermittent devices
• Some MSP430 boards come with FRAM, non-volatile storage that is critical to maintaining state and data through the regular power losses of intermittent devices.