Having studied some phonetics myself, I would second the value of the IPA.
English simply does not work as a standard. As with any language, English
varies in pronunciation across space as well as time. Consider how the same
English word will vary drastically from London to Wales, much less Ireland,
Canada, Texas, Australia, South Africa etc. The IPA provides an objective
description which people from different varieties of different languages
may use as an accurate reference point.