Whilst I agree that boasting about who has a few MPH more than the next-player is not especially interesting there is a very valid reason to learn how to break with the most speed you can without losing control.
The reason is breaking conditions change, even on the same table. A break that may work consistently at slower speeds (sub-20mph) on one table at one time may not work on another table, or even the same table at a different time. This is why I think a well-rounded player needs to learn a strong power break. You won't need it all the time but just like that 4-rail-force-follow-with-inside english shot it's a great tool to have handy when the situation calls for it.
One piece of advice I can't stand that you see in a lot of instructional books is to always break controlled and level and don't let the cue ball hop up on contact. Even the otherwise excellent book "The Great Break Shot" by Charley Bond gives the same advice but yet it has photos of multiple Pros breaking on the cover hopping the cue ball a foot off the bed of the table. If this is bad way to play a break shot you can bet the Pros would not be doing it. Yes, if you are a beginner player you can make many more mistakes breaking hard than soft, but sooner or later you have to learn how to do it or your game will be limited to situations where a soft break works well.
Of course just because you can break at 30mph does not mean you always should. Recently I was playing someone with a very powerful break, not sure the speed but consistently making 1-3 balls on every break in 9 Ball. However if he failed to get a shot on the next ball he would leave me a very easy spread, so it's a double-edged sword. You need to ensure your break is not better than the rest of your game!
Yeah, I agree with you. It's not bad to have. Although I don't exactly have earth-shattering speed in my arm, I do have a pretty sporty break when needed and I'll bring it out in select situations. Like, if I'm in a desperate situation and looking for a miracle. As well, barbox 8ball almost requires you to break as hard as you can (unless you're Corey Deuel, that is).