I think you're taking this too far.

You can setup real debian, and some of the apps inside the debian will not work - but your phone will continue working fine.

There is no device right now that fits in your pocket that is going to be identical to your desktop. The hardware simply isn't there.

With easy debian you can install and upgrade whatever you want... if you break your debian installation - just blow it away and re-download the easy debian tarball and start over.

At no point did you hurt your phone.

If, OTOH, you start dabbling in porting software to maemo and start running things through maemo, or try installing debian deb's directly into the phone OS - then you can sudo-brick the phone. (nothing a reflash can't fix. In fact, I did my first "brick" last night by trying to make the phone auto-mount my ext3 formatted SD card. It wouldn't boot, because I did something wrong. I was back up and running in 10 minutes with a reflash and restore from backup).

Seriously, you can do what you want to it.. and then recover from it. The choices are yours.

But no - you're not really going to learn how to "use" Linux fully if the only Linux you have is in your pocket. But if your desktop and your phone are both Linux then you'll find you'll start learning quickly, and what you learn on one will be of use on the other (assuming they are both debian(based)).

Now, MeeGo OTOH is RPM based and not DEB based. So if you decide to start playing with MeeGo (which i intend to once there is a decent open UI and the phone works; thats my only requirements) - then what you learn on MeeGo may not be totally useful on Ubuntu desktop because the packaging system is different. You'll still get what makes Linux, Linux - but installing and removing packages will be different.

If you go MeeGo, it might be better to use Fedora on the Desktop for a totally similar solution between systems.