It also allows you to stand _behind_ the camera when shooting, a not
insignificant point in many situations!

I have the Canon RC-1 infrared remote for my Digital Rebel (300D). It
also locks open the shutter. If you have the camera in bulb mode, then
when you press the button on the remote, the shutter opens, and it
remains open until you push the remote button a second time. In other
words, you don't have to hold down the button during the exposure -
it's one press to open the shutter and another to close.

During "normal" operation (i.e. not bulb mode), the remote can trigger
the camera's shutter either immediately or after a two-second delay.

I recently bought a cheap wired remote, and now use that more often
than the wireless one, but I still use both. Last time I used the
wireless remote it was giving me a lot of trouble (it seemed to only
have a range of a couple meters) but I suspect that either the
batteries are dying, or (more likely) the fluorescent lighting in the
building was interfering with the IR transmission.

Before I had the wired remote, I often used the wireless one with the
camera on the tripod by simply reaching around and pointing the remote
back at the camera from the front. A little awkward, but not very. I
like the wired remote better for that, though; it's more convenient,
and has a two-stage focus/shutter button. (I'm using the cheap Adidt
wired remote that you can always find on Ebay. It's worked great so
far.)

- Darryl