The valuable thing about the standard Egyptological pronunciation is that people can sit around a table, read a text, and understand what is being read without having to learn a strange new phonetic inventory. How close it sounds to the real thing is irrelevant for what it's used for. Anyone using phonetics to look at how Egyptian changed over time isn't using standard Egyptological pronunciation to do so. While Stuart Tyson Smith's reconstruction of an Egyptologist-approved dialect of Egyptian for the Stargate movie is pretty fun, it's not like we have any native speakers we can communicate with.