Jeff: I can tell a couple of reasons for doing it in that "silly" way:

• It will make the network tool a bit closer to the instant-apply model
• It will allow this in a non-intrusive way ("why the f*ck have my config files changed if I didn't click the OK button?" :)

Danilo: I have to agree with you that dial-up is a bit buggy (it's hard to code something you can't test, and specifically in debian has switched from wvdial to pppconfig-like), but those aren't the reasons for this, the config is modified too in the distro specific config files when the user agrees to do so, as I answered to jeff, it's more related to instant-apply and user-frienlyness

In another GNOME related stuff, I got my Guadec talk rejected, it seems that my proposal wasn't interesting enough... *shrug*