When using #include "Arduino.h" sei() and cli() should be available but both ways should work alike.
Just one thing to be careful about. While an Arduino doesn’t do a lot else than running your code, Particle devices do other stuff while not occupied with your code (e.g. cloud house keeping) which might get affected by disabling interrupts for prolonged periods.
If you are not using SYSTEM_THREAD(ENABLED) delay() does (try to) attend to the cloud every second (unless you prevent it by disabling interrupts) and with multi threading disabling interrupts might have even more impact.