In a phone you want fairly high burst performance as most of your usage scenarios are bursty.
That's a meaningless statement. Of course most of the usage scenarios are bursty. That has been true with desktop and laptop PCs as well.
The issue with the ARM vendors, however, is not that they want to put their best foot forward when it comes to burst performance. That's understandable.
Instead, the issue is that the ARM vendors have code somewhere in the OS that will look for specific benchmark applications to run, then crank up the clock speeds artificially, i.e. without any regard to battery life or thermal limits.