Why bother?

For second-language learners or people undergoing treatment for language disorders, the first major goal is to be able to make the same contrasts that the rest of the speech community does. E.g.,

• English contrasts like hit and heat, or hit and hid.
• French contrasts like [lu] loup 'wolf' and [ly] lu 'read', or the nasalization contrast between sec 'dry' and cinq 'five'.

The minimal contrasts expressed in broad transcriptions aren't good enough if:

• you want an even better accent in a second language.
• the problem is you're pronouncing the contrasts, but not noticeably enough for listeners to hear the difference.
• you want to do linguistic research
  • on a new language, where you don't know ahead of time what the phoneme groupings will be
  • on dialect differences, where most of the interesting differences will be too small to change meanings