There are times when you need to shout to make yourself heard over the din. Strident voices are all about that overwhelming power that makes everyone around them stop and take notice. If you need a loud, proud vocal read with the volume turned to 11, then this is the right voice type for you.
Some matters require a voice type that embodies urgency, gravity, and doesn't fool around. The strident voice is there for when subtletly needs to fly out the window, and a character has to rise above the hustle and bustle that others are making. There are others characters still that just talk so loud that you'd be able to hear them from a mile away. If your script is calling for hars-sounding, loud, brash performance, then these actors and actresses are ready to give it their all.
There are many characters that can use a strident voice to its fullest potential. Anime is certainly one of the mediums that most frequently uses stridence and volume in its favor, and video games have borrowed many of these tropes for their own use. Whether it's shouting the name of an ultimate attack at the top of their lungs, or delivering exposition to other characters in a volume that's way higher than appropriate, loudness can be an asset to many characters. A strident voice can also have plenty of voices in advertising and marketing as well; ads for hearing aids and PSAs for noise pollution are excellent examples.
Loud, harsh, brash, and over-the-top. Those are the qualities that most define the booming nature of the strident voice.