Eric A. Hall <ehall@ehsco.com> was seen to declaim:
Nobody is forcing anybody to adopt it. I think the point is people with non-compliant maillers delete mails with attachments and no body on sight... sometimes, in an automated rule. If you don't care that a percentage of your recipients don't ever get to see your missives (and/or think you are infected with some sort of virus) as long as those that use the same software as you do, then you are in good company - its how most web designers seem to feel about Internet Explorer and flash.
OTOH, complaining to people who use the spec about problems with your own mailer is pretty dumb. As has already been pointed out, just because a standard exists is not a good reason to use it if there is a more backwards-complaint standard that does the same job - like clearsigning the message in the body. As an (extreme) counter-example, there are standards I would be compliant with if I had decided to start each paragraph with a pretty illuminated capital (using a gif image), change the font to a nice, bubbly font in ebcdic order (and include a AOT file for that) and then wrap the whole thing up in mime multipart/related so that a *compliant* reader could view it. however, I am fairly sure that would get me booted from the list *and* would be megabytes of unreadable garbage to most of the list (it is probably unreadable garbage now, but that is just their personal opinion of my emails :) Just because it is a standard, doesn't mean it is appropriate.