As far as the dangers of SSHing into your device, I don't really see it. Sure, you might screw something up, so what? A simple restore will take care of things. You can't edit the bootloader files to really mess things up, and most jailbreak users probably don't spend much time directly accessing the file system in the first place. I think more people should, but then again I am an engineer and breaking things and then getting them working again is some perverse idea of fun to me.
Maybe it is a generational thing. I was playing with computer file systems back when it was considered a perfectly healthy thing to do. It lead me to some wonderfully fulfilling things like having code integrated into open source software that is still in use today (quite possibly even buried somewhere in OSX ...). I'm glad I didn't have people trying to scare me away from such endeavors back then and I won't be the one to do it today.