A copper pot is probably 10 times thicker than your pipes. coupled with the risk of cracking through work-hardening, copper is just a risk you don't need to take IMO. non SAE R30 J6 rubber hoses can be eaten through within 12 months, copper can take 12 years but I prefer my cars to last bit longer
http://www.dieselnet.com/news/2014/07nist.php - bear in mind that report says 15 years for 1.2mm copper and the stuff we use in brakes is normlly 0.7mm.