Mixing though an MP3 Emulator

Hey guys,
Was wondering if any of you do this?

I check and mix through the Sonnox Fraunhofer plugin. Settings at 256kbps - AAC. Then, I disable it when bouncing.

I feel like this gives me a ‘truer’ representation of how my mix will sound after compression artifacts and so-forth.

If you do this, what do you feel like your benefitting the most of it from. And if you don’t (assuming if you have it), why not?