if u go buy a china make phone, the speaker beats any of the others in the market like sony, nokia etc..
No. hold one there. you're dead wrong. if you've never heard or used some of the devices you're speaking of, you shouldnt speak period. you've obviously never heard, much less seen a Nokia N95. Stereo speakers, that are louder than any of my laptops. i use it as a stereo while playing poker, or outside relaxing. sony ericsson's also have VERY good quality speakers.
this china crap that your talking about, which you didnt even mention any particular phone at all....if your talking about that bootleg iphone, i've seen them, and theyre embarassing.
and to answer your question, how the hell are WE supposed to know why apple put these speakers in the iphone?? ask apple.