running new brake line questions

[bagged01extcab]

Ok, I have always heard everyone say "don't use compression fittings on brake lines", but why? I would think that stainless steel tubing and compression fittings would be safe for the brake pressure? Exactly how much pressure is your average brake system? I need to run all new lines and repop lines will not work as I have done to many mods to the frame. I have 1/4" ss tubing but my flaring tool would never flare the ends. I thought that I had seen some aluminum brake lines somewhere but cant find it. Suggestions?

Thanks