[exim] SMTP vs Submission (port 25 vs 587)

I've been searching for information about why it is a good idea to use 587
instead of 25 but have not found anything convincing. I have hit a brick
wall where I work since they think that 587 is non-standard (Even after
showing them RFC 4409) and thus is not wise. Can anyone provide me with any
links or anything that would argue this case? Unfortunately, email archives
are not valid for this.

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Lab tests show that use of micro$oft causes cancer in lab animals
Got Gas???