Czajunia:
I am not trying to convince you to use the VOIP. I use skype out (instead of "skype voip") to call phone numbers exactly because of the reasons you mentioned before.

I am just curious how this could work. Do you know if you could place a call without ALSO having a data connection?

I can only imagine two options for this to work:

1) the software on your phone would communicate (send data) with some server "saying" that I call was about to be made to X from Y and then the phone would call a pre-defined number that would be waiting for your call and would recognize who you want to call (X) based on the caller id (Y). Google voice can work somewhat like this but it actually calls you back.

2) The application would call a pre-defined number that would recognize you based on your caller id and would get who you want to call using DTMF. That is how skype out works.

Option 1 would require also using the "data channel". On option2 I can imagine you could somehow use dtmf tones to tell the system about the "skype account" but, as far as I know, you can't call "skype" accounts (just phone numbers) using skype out.

The "missing link" is how you can call a skype account using just the "voice channel" (no data)