Scrivere una frase TUTTA IN MAIUSCOLO, CON L’INTENTO DI ENFATIZZARLA, può in realtà rivelarsi controproducente, risultando meno leggibile:

Because we see words as shapes, big rectangular blocks of all caps take us much longer to process. In an emergency, that extra time to decipher an urgent message may come at a cost. […]

So why do we use all caps instead of bold or italic or even highlighted? Because back when lawyers used typewriters, the only simple way to emphasize anything was to use ALL CAPS. And while today our fancy post-typewriter machines could certainly render the text in other “conspicuous” ways, tradition is hard to break. Just ask the weather service.