Basically, there are 4 temperature indications.
1. BLUE temperature light means that your engine is below normal operating temperature,
2. NO temperature light means things are normal,
3. FLASHING RED temperature light means that engine is above operating temperature and you should pull over soon,
4. SOLID RED LIGHT means that you are overheated, and to pull over immediately.
^ This is why Mazda's blue/red/flashing red system is better than a questionably accurate temp gauge that gets ignored by many drivers.
Also because this engine has DI and a longer warmup period, the blue light is a helpful reminder to drive moderately until blue light goes out.
I have another car with DI (and a longish warmup period) and a normal temp gauge and it's more tedious to monitor when the engine is warmed up for hard driving.