hi

i think it is still ok and worth considering - you will not loose words of conversation as the noise of the handset speaker is still loud enough !

sometimes during conversation it is too loud (imagine your boss yelling at you) and you like to hold the speaker some cm off the ear. then it immediately turns the speakers on and it is even more louder.

one other example - hold the phone at your right hand and sometimes the sensor is not close enough to the head to keep the loud-speaker off.
no problem with left/ear hand though !

ciao