Wristwatch mobiles and the first smartphone

The world's first smartphone ran a kind of DOS (sic!) and now celebrates its twelfth anniversary.
The fact that it had a backlit screen had even singled it out among PDAs and palmtops of that time.

http://cdecas.free.fr/computers/pocket/simon.php
http://www.byte.com/art/9412/sec11/art3.htm

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The wristphone is a commendable idea at least theoretically, and its last (?!) noted implementation is now three years old. One drawback of these phones might be potential unsafety of the battery - some rechargeable batteries can explode; does not happen very often though.

Who could specially like to wear a wristwatch phone? I think:
(1) people who often have busy hands (industrial/manual workers, pilots, drivers);
(2) people who tend to lose things (forgetfulness);
(3) people who, on a particular occasion - perhaps for fashion or etiquette reasons, do not have a pocket or purse to put a regular phone in but still would need to take a phone with them.

http://www.simonperry.org/dst/archives/001565.html
http://www.theregister.co.uk/2003/05/02/chuck_out_your_handsets_here/

You can find pictures of IBM Simon, 1994 (quite scarce), and of wristwatch phones (somewhat less scarce) on the web.